36 results on '"Magdalene M. Assimon"'
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2. SARS-CoV-2 spike-protein targeted serology test results and their association with subsequent COVID-19-related outcomes
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Harvey W. Kaufman, Stanley Letovsky, William A. Meyer, Laura Gillim, Magdalene M. Assimon, Carly A. Kabelac, John W. Kroner, Shannon L. Reynolds, and Marcia Eisenberg
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SARS-CoV-2 spike antibody ,SARS-CoV-2 ,COVID-19 ,immunocompromised conditions ,immune protection ,Public aspects of medicine ,RA1-1270 - Abstract
ImportanceIn the absence of evidence of clinical utility, the United States' Centers for Disease Control and Prevention does not currently recommend the assessment of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike-protein antibody levels. Clinicians and their patients, especially immunocompromised patients, may benefit from an adjunctive objective clinical laboratory measure of risk, using SARS-CoV-2 serology.ObjectiveThe aim of this study is to estimate the association between SARS-CoV-2 spike-protein targeted antibody levels and clinically relevant outcomes overall and among clinically relevant subgroups, such as vaccine and immunocompetency statuses.DesignA retrospective cohort study was conducted using laboratory-based data containing SARS-CoV-2 antibody testing results, as well as medical and pharmacy claim data. SARS-CoV-2 testing was performed by two large United States-based reference clinical laboratories, Labcorp® and Quest Diagnostics, and was linked to medical insurance claims, including vaccination receipt, through the HealthVerity Marketplace. Follow-up for outcomes began after each eligible individual's first SARS-CoV-2 semiquantitative spike-protein targeted antibody test, from 16 November 2020 to 30 December 2021.ExposuresExposure is defined as having SARS-CoV-2 spike-protein targeted antibody testing.Main outcomes and measuresStudy outcomes were SARS-CoV-2 infection and a serious composite outcome (hospitalization with an associated SARS-CoV-2 infection or all-cause death). Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Propensity score matching was used for confounding covariate control.ResultsIn total, 143,091 (73.2%) and 52,355 (26.8%) eligible individuals had detectable and non-detectable levels of SARS-CoV-2 spike-protein targeted antibodies, respectively. In the overall population, having detectable vs. non-detectable antibodies was associated with an estimated 44% relative reduction in SARS-CoV-2 subsequent infection risk (HR, 0.56; 95% CI 0.53–0.59) and an 80% relative reduction in the risk of serious composite outcomes (HR 0.20; 95% CI 0.15–0.26). Relative risk reductions were observed across subgroups, including among immunocompromised persons.Conclusion and relevanceIndividuals with detectable SARS-CoV-2 spike-protein targeted antibody levels had fewer associated subsequent SARS-CoV-2 infections and serious adverse clinical outcomes. Policymakers and clinicians may find SARS-CoV-2 spike-protein targeted serology testing to be a useful adjunct in counseling patients with non-detectable antibody levels about adverse risks and reinforcing appropriate actions to mitigate such risks. more...
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- 2023
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3. QT-Prolonging Antibiotics, Serum-to-Dialysate Potassium Gradient, and Risk of Sudden Cardiac Death Among Patients Receiving Maintenance HemodialysisPlain Language Summary
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Patrick H. Pun, Magdalene M. Assimon, Lily Wang, Sana M. Al-Khatib, M. Alan Brookhart, David J. Weber, Wolfgang C. Winkelmayer, and Jennifer E. Flythe
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Azithromycin ,dialysate potassium ,fluoroquinolones ,hemodialysis ,sudden cardiac death ,USRDS ,Diseases of the genitourinary system. Urology ,RC870-923 - Abstract
Rationale & Objective: Treatment with certain QT interval-prolonging antibiotics is associated with a higher risk of sudden cardiac death among individuals with hemodialysis-dependent kidney failure. Concurrent exposure to large serum-to-dialysate potassium gradients, which promote large potassium shifts, may augment the proarrhythmic effects of these medications. The primary objective of this study was to examine whether the serum-to-dialysate gradient modifies the cardiac safety of azithromycin, and separately, levofloxacin/moxifloxacin. Study Design: Retrospective observational cohort study using a new-user study design. Setting & Population: Adult in-center hemodialysis patients with Medicare coverage in the US Renal Data System (2007-2017). Exposure: Initiation of azithromycin (or levofloxacin/moxifloxacin) as compared to amoxicillin-based antibiotics (exposure). Serum-to-dialysate potassium gradient (effect modifier). Individual patients could contribute multiple study antibiotic treatment episodes to the analyses. Outcomes: Sudden cardiac death (14 days). Analytical Approach: Inverse probability of treatment-weighted survival models to estimate HRs and robust 95% CIs. Results: The azithromycin versus amoxicillin-based antibiotic cohort included 89,379 unique patients with 113,516 azithromycin and 103,493 amoxicillin-based treatment episodes. Azithromycin versus amoxicillin-based antibiotic treatment was associated with a higher risk of sudden cardiac death overall, HR, 1.68; 95% CI, 1.31-2.16. The risk was numerically higher when the baseline serum-to-dialysate potassium gradient was ≥3 mEq/L compared with more...
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- 2023
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4. Diuretic Use Among Patients Receiving Hemodialysis in the United States
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Jennifer E. Flythe, MD, MPH and Magdalene M. Assimon, PharmD, PhD
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Diseases of the genitourinary system. Urology ,RC870-923 - Published
- 2022
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5. Feasibility of Tablet-Based Patient-Reported Symptom Data Collection Among Hemodialysis Patients
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Jennifer E. Flythe, Matthew J. Tugman, Julia H. Narendra, Adeline Dorough, Johnathan Hilbert, Magdalene M. Assimon, and Darren A. DeWalt
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hemodialysis ,implementation ,improvement ,mixed methods ,patient-reported outcomes ,quality ,Diseases of the genitourinary system. Urology ,RC870-923 - Abstract
Introduction: Individuals receiving in-center hemodialysis have high symptom burdens but often do not report their symptoms to care teams. Evidence from other diseases suggest that use of symptom electronic patient-reported outcome measures (ePROMs) may improve outcomes. We assessed the usability of a symptom ePROM system and then implemented a quality improvement (QI) project with the objective of improving symptom communication at a US hemodialysis clinic. During the project, we assessed the feasibility of ePROM implementation and conducted a substudy exploring the effect of ePROM use on patient-centered care. Methods: After conducting usability testing, we used mixed methods, guided by the Quality Implementation Framework, to implement a 16-week symptom ePROM QI project. We performed pre-, intra-, and postproject stakeholder interviews to identify implementation barriers and facilitators. We collected ePROM system-generated data on symptoms, e-mail alerts, and response rates, among other factors, to inform our feasibility assessment. We compared pre- and postproject outcomes. Results: There were 62 patient participants (34% black, 16% Spanish-speaking) and 19 care team participants (4 physicians, 15 clinic personnel) at QI project start, and 32 research participants. In total, the symptom ePROM was administered 496 times (completion rate = 84%). The implementation approach and ePROM system were modified to address stakeholder-identified concerns throughout. ePROM implementation was feasible as demonstrated by the program’s acceptability, demand, implementation success, practicality, integration in care, and observed trend toward improved outcomes. Conclusions: Symptom ePROM administration during hemodialysis is feasible. Trials investigating the effectiveness of symptom ePROMs and optimal administration strategies are needed. more...
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- 2020
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6. Use of QT Prolonging Medications by Hemodialysis Patients and Individuals Without End‐Stage Kidney Disease
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Magdalene M. Assimon, Lily Wang, Patrick H. Pun, Wolfgang C. Winkelmayer, and Jennifer E. Flythe
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Hemodialysis ,patterns of use ,QT prolonging medications ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Background The rate of sudden cardiac death in the hemodialysis population exceeds that of the general population by >20‐fold. Hemodialysis patients may be particularly susceptible to sudden cardiac death provoked by drug‐induced QT prolongation because of their substantial cardiovascular disease burden, exposure to electrolyte shifts during dialysis, and extensive polypharmacy. However, population‐specific data regarding the frequency and patterns of QT prolonging medication use are limited. Methods and Results We conducted a descriptive drug utilization study using 3 administrative databases, the United States Renal Data System, MarketScan, and Medicare claims. We characterized the extent and patterns of QT prolonging medication use by adult hemodialysis patients and individuals without end‐stage kidney disease annually from 2012 to 2016. We also identified instances of high‐risk QT prolonging medication use among hemodialysis patients. In total, 338 515 hemodialysis patients and 40.7 million individuals without end‐stage kidney disease were studied. Annual utilization rates of QT prolonging medications with known torsades de pointes risk in hemodialysis patients were ~1.4 to ~2.5 times higher than utilization rates in individuals without end‐stage kidney disease. Hemodialysis patients with demographic and clinical risk factors for drug‐induced QT prolongation were exposed to medications with known torsades de pointes risk more often than patients without risk factors. Conclusions Hemodialysis patients use QT prolonging medications with known torsades de pointes risk more extensively than individuals without end‐stage kidney disease. Given the widespread use and instances of high‐risk prescribing, future studies evaluating the cardiac safety of these drugs in the hemodialysis population are needed. more...
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- 2020
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7. Target weight achievement and ultrafiltration rate thresholds: potential patient implications
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Jennifer E. Flythe, Magdalene M. Assimon, and Robert A. Overman
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Hemodialysis ,Target weight ,Volume overload ,Ultrafiltration rate ,Quality Incentive program ,Diseases of the genitourinary system. Urology ,RC870-923 - Abstract
Abstract Background Higher ultrafiltration (UF) rates and extracellular hypo- and hypervolemia are associated with adverse outcomes among maintenance hemodialysis patients. The Centers for Medicare and Medicaid Services recently considered UF rate and target weight achievement measures for ESRD Quality Incentive Program inclusion. The dual measures were intended to promote balance between too aggressive and too conservative fluid removal. The National Quality Forum endorsed the UF rate measure but not the target weight measure. We examined the proposed target weight measure and quantified weight gains if UF rate thresholds were applied without treatment time (TT) extension or interdialytic weight gain (IDWG) reduction. Methods Data were taken from the 2012 database of a large dialysis organization. Analyses considered 152,196 United States hemodialysis patients. We described monthly patient and dialysis facility target weight achievement patterns and examined differences in patient characteristics across target weight achievement status and differences in facilities across target weight measure scores. We computed the cumulative, theoretical 1-month fluid-related weight gain that would occur if UF rates were capped at 13 mL/h/kg without concurrent TT extension or IDWG reduction. Results Target weight achievement patterns were stable over the year. Patients who did not achieve target weight (post-dialysis weight ≥ 1 kg above or below target weight) tended to be younger, black and dialyze via catheter, and had shorter dialysis vintage, greater body weight, higher UF rate and more missed treatments compared with patients who achieved target weight. Facilities had, on average, 27.1 ± 9.7% of patients with average post-dialysis weight ≥ 1 kg above or below the prescribed target weight. In adjusted analyses, facilities located in the midwest and south and facilities with higher proportions of black and Hispanic patients and higher proportions of patients with shorter TTs were more likely to have unfavorable facility target weight measure scores. Without TT extension or IDWG reduction, UF rate threshold (13 mL/h/kg) implementation led to an average theoretical 1-month, fluid-related weight gain of 1.4 ± 3.0 kg. Conclusions Target weight achievement patterns vary across clinical subgroups. Implementation of a maximum UF rate threshold without adequate attention to extracellular volume status may lead to fluid-related weight gain. more...
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- 2017
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8. Antihyperglycemic Medication Use Among U.S. Adults With Hemodialysis-Dependent Kidney Disease and Comorbid Diabetes
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Klara R. Klein, Virginia Pate, Magdalene M. Assimon, Til Stürmer, John B. Buse, and Jennifer E. Flythe
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Advanced and Specialized Nursing ,Endocrinology, Diabetes and Metabolism ,Internal Medicine - Published
- 2022
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9. The Non-Inferiority Complex: What Do Non-Inferiority Trials Tell Us?
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Magdalene M. Assimon, Gary R. Cutter, and Joanne M. Bargman
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Research Design ,Nephrology ,Perspective ,General Medicine - Published
- 2022
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10. letter to the editor
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Magdalene M. Assimon, Patrick H. Pun, Lily Wang, Sana M. Al-Khatib, M. Alan Brookhart, David J. Weber, Wolfgang C. Winkelmayer, and Jennifer E. Flythe
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Nephrology - Published
- 2022
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11. 17-LB: Antihyperglycemic Use in Hemodialysis-Dependent Kidney Failure
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KLARA KLEIN, VIRGINIA PATE, MAGDALENE M. ASSIMON, TIL STÜRMER, JOHN B. BUSE, and JENNIFER FLYTHE
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Endocrinology, Diabetes and Metabolism ,Internal Medicine - Abstract
Background: At least two-thirds of people with hemodialysis-dependent kidney failure have comorbid diabetes which associates with higher mortality. Some GLP-1 receptor agonists (RA) do not require renal dosing and could uniquely benefit dialysis patients, individuals with tremendous cardiovascular disease burden. Methods: Using data from a national surveillance system for kidney failure in the U.S. that includes Medicare Part D prescription drug claims, we: 1) calculated the quarterly prevalence of antihyperglycemic use among diabetic hemodialysis patients from 2012 to 2017 and 2) characterized antihyperglycemic users in October 2017. Results: Among the 129,865 hemodialysis patients with comorbid diabetes, insulin was the most prescribed agent (33%) , followed by sulfonylureas (SU, 7%) and DPP4 inhibitors (DPP4i, 5%) in October 2017. SU use fell, and DPP4i use rose from 2012 to 2017. Less than 5% of patients received combination therapy (insulin + a 2nd agent; Figure 1) . Disregarding kidney disease as an atherosclerotic cardiovascular disease (ASCVD) risk factor, 64% of patients met American Diabetes Association ASCVD criteria and 98% were at high risk for ASCVD in 2017. GLP-1 RA were prescribed to Conclusions: GLP-1 RA use by hemodialysis patients is limited. There is compelling need to establish the safety and efficacy of GLP-1 RA in this high-risk population. Disclosure K. Klein: None. V. Pate: None. M. M. Assimon: None. T. Stürmer: Research Support; Novo Nordisk. Stock/Shareholder; Novartis AG, Novo Nordisk, Roche Pharmaceuticals. Other Relationship; AbbVie Inc., Boehringer Ingelheim International GmbH, GlaxoSmithKline plc., Takeda Pharmaceutical Company Limited, UCB, Inc. J. B. Buse: Consultant; Alkahest, Anji, AstraZeneca, Boehringer Ingelheim International GmbH, Cirius Therapeutics, Inc., Eli Lilly and Company, Fortress biotech, GentiBio, Glycadia, Glyscend, Janssen Pharmaceuticals, Inc., Mellitus Health, Moderna, Inc., Pendulum Therapeutics, Praetego, LLC, Stability Health, Valo, Zealand Pharma A/S. Research Support; AstraZeneca, Dexcom, Inc., Eli Lilly and Company, Novo Nordisk, vTv Therapeutics. Stock/Shareholder; Glyscend, Mellitus Health, Pendulum Therapeutics, PhaseBio Pharmaceuticals, Inc., Praetego, LLC, Stability Health. Other Relationship; Adocia, AstraZeneca, Eli Lilly and Company, Intarcia Therapeutics, Inc., MannKind Corporation, Novo Nordisk, Sanofi, Senseonics, vTv Therapeutics. J. Flythe: Advisory Panel; Fresenius Medical Care. Consultant; AstraZeneca. Research Support; Fresenius Medical Care. more...
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- 2022
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12. Efficacy, Safety, and Tolerability of Oral Furosemide Among Patients Receiving Hemodialysis: A Pilot Study
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Jennifer E. Flythe, Magdalene M. Assimon, Matthew J. Tugman, Julia H. Narendra, Simran K. Singh, Wanting Jin, Quefeng Li, Nisha Bansal, Thomas H. Hostetter, and Laura M. Dember
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Nephrology - Abstract
Diuretic use may reduce volume-related complications in hemodialysis. We evaluated the efficacy, safety, and tolerability of furosemide in patients with hemodialysis-dependent kidney failure.We conducted an open label, single-arm, 18-week, dose titration pilot study of oral furosemide (maximum dose 320 mg/day) among patients receiving maintenance hemodialysis who reported at least 1 cup of urine output per day. The primary efficacy outcome was an increase from baseline to a specified threshold of 24-hour urine volume, with the threshold based on baseline urine volume (200 ml/dayOf the 39 participants, 28 (72%) received the expected furosemide dose, 3 (8%) underwent dose reduction, 5 (12%) discontinued furosemide without dose reduction, and 3 (8%) underwent dose reduction and subsequently discontinued furosemide. The median (quartile 1, quartile 3) baseline 24-hour urine volume was 290 ml (110, 740), and the maximum, average daily study furosemide dose ranged from 69 mg/day to 320 mg/d. The urine output efficacy outcome was met by 12 (33%), 11 (33%), and 7 (22%) participants at weeks 5, 12, and 18, respectively, in the intention-to-treat analysis, and by 12 (39%), 9 (35%), and 7 (28%) participants at weeks 5, 12, and 18, respectively, in the on-treatment analysis. There were no electrolyte, furosemide level, or patient-reported hearing change safety events.Furosemide was generally safe and well tolerated, but only one-third of participants met the efficacy definition at week 5. The clinical importance of the efficacy findings is uncertain. more...
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- 2022
13. Zolpidem Versus Trazodone Initiation and the Risk of Fall-Related Fractures among Individuals Receiving Maintenance Hemodialysis
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Jennifer E. Flythe and Magdalene M. Assimon
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Male ,Zolpidem ,medicine.medical_specialty ,Epidemiology ,medicine.drug_class ,Nonbenzodiazepine ,Medicare ,Critical Care and Intensive Care Medicine ,Dizziness ,Drug Prescriptions ,Hypnotic ,Fractures, Bone ,Renal Dialysis ,Sleep Initiation and Maintenance Disorders ,Internal medicine ,medicine ,Humans ,Cognitive Dysfunction ,Registries ,Renal Insufficiency, Chronic ,Aged ,Retrospective Studies ,Transplantation ,business.industry ,Hazard ratio ,Absolute risk reduction ,Trazodone ,Retrospective cohort study ,Original Articles ,Middle Aged ,United States ,Confidence interval ,Hospitalization ,Nephrology ,Sleep Aids, Pharmaceutical ,Accidental Falls ,Female ,business ,medicine.drug - Abstract
Background and objectives Zolpidem, a nonbenzodiazepine hypnotic, and trazodone, a sedating antidepressant, are the most common medications used to treat insomnia in the United States. Both drugs have side effect profiles (e.g., drowsiness, dizziness, and cognitive and motor impairment) that can heighten the risk of falls and fractures. Despite widespread zolpidem and trazodone use, little is known about the comparative safety of these medications in patients receiving hemodialysis, a vulnerable population with an exceedingly high fracture rate. Design, setting, participants, & measurements Using data from the United States Renal Data System registry (2013–2016), we conducted a retrospective cohort study to investigate the association between the initiation of zolpidem versus trazodone therapy and the 30-day risk of hospitalized fall-related fractures among Medicare-enrolled patients receiving maintenance hemodialysis. We used an active comparator new-user design and estimated 30-day inverse probability of treatment-weighted hazard ratios and risk differences. We treated death as a competing event. Results A total of 31,055 patients were included: 18,941 zolpidem initiators (61%) and 12,114 trazodone initiators (39%). During the 30-day follow-up period, 101 fall-related fractures occurred. Zolpidem versus trazodone initiation was associated with a higher risk of hospitalized fall-related fracture (weighted hazard ratio, 1.71; 95% confidence interval, 1.11 to 2.63; weighted risk difference, 0.17%; 95% confidence interval, 0.07% to 0.29%). This association was more pronounced among individuals prescribed higher zolpidem doses (hazard ratio, 1.85; 95% confidence interval, 1.10 to 3.01; and risk difference, 0.20%; 95% confidence interval, 0.04% to 0.38% for higher-dose zolpidem versus trazodone; and hazard ratio, 1.60; 95% confidence interval, 1.01 to 2.55 and risk difference, 0.14%; 95% confidence interval, 0.03% to 0.27% for lower-dose zolpidem versus trazodone). Sensitivity analyses using longer follow-up durations yielded similar results. Conclusions Among individuals receiving maintenance hemodialysis, zolpidem initiators had a higher risk of hospitalized fall-related fracture compared with trazodone initiators. Podcast This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2020_12_18_CJN10070620_final.mp3 more...
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- 2020
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14. Analysis of Respiratory Fluoroquinolones and the Risk of Sudden Cardiac Death Among Patients Receiving Hemodialysis
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Magdalene M. Assimon, Jennifer E. Flythe, Patrick H. Pun, David J. Weber, Lily Wang, Sana M. Al-Khatib, M. Alan Brookhart, and Wolfgang C. Winkelmayer
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Male ,medicine.medical_specialty ,medicine.medical_treatment ,Population ,Respiratory Tract Diseases ,Sudden cardiac death ,Moxifloxacin ,Levofloxacin ,Renal Dialysis ,Risk Factors ,Internal medicine ,medicine ,Humans ,education ,Retrospective Studies ,Original Investigation ,education.field_of_study ,business.industry ,Incidence ,Hazard ratio ,Retrospective cohort study ,Amoxicillin ,Middle Aged ,medicine.disease ,United States ,Anti-Bacterial Agents ,Survival Rate ,Death, Sudden, Cardiac ,Population Surveillance ,Kidney Failure, Chronic ,Female ,Hemodialysis ,Cardiology and Cardiovascular Medicine ,business ,medicine.drug ,Fluoroquinolones ,Follow-Up Studies - Abstract
Importance Respiratory fluoroquinolone antibiotics are some of the most common medications with QT interval-prolonging potential prescribed to patients with hemodialysis-dependent kidney failure-individuals who have a very high risk of sudden cardiac death (SCD). To date, there have been no large-scale, population-specific studies evaluating the cardiac safety of respiratory fluoroquinolones in the hemodialysis population. Objective To investigate the cardiac safety of respiratory fluoroquinolones among individuals with hemodialysis-dependent kidney failure. Design, setting, and participants A retrospective cohort study examining safety using an active comparator new-user design was conducted using administrative claims data from a US-wide kidney failure registry from January 1, 2007, to December 31, 2016, including 264 968 Medicare beneficiaries receiving in-center maintenance hemodialysis. Data analysis was performed from January 4 to August 16, 2021. Exposures Respiratory fluoroquinolone (levofloxacin or moxifloxacin) vs amoxicillin-based (amoxicillin or amoxicillin with clavulanic acid) antibiotic treatment. Main outcomes and measures Sudden cardiac death within 5 days of outpatient initiation of a study antibiotic. Inverse probability of treatment-weighted survival models to estimate hazard ratios (HRs), risk differences (RDs), and corresponding 95% CIs. Death due to a cause other than SCD was treated as a competing event. Fracture was considered as a negative control outcome. Results The study cohort included 264 968 unique in-center hemodialysis patients and 626 322 study antibiotic treatment episodes: 251 726 respiratory fluoroquinolone treatment episodes (40.2%) and 374 596 amoxicillin-based treatment episodes (59.8%). Of the 264 968 patients, 135 236 (51.0%) were men, and the mean (SD) age was 61 (15) years. Respiratory fluoroquinolone vs amoxicillin-based antibiotic treatment was associated with a higher relative and absolute 5-day risk of SCD (weighted HR, 1.95; 95% CI, 1.57-2.41; and weighted RD per 100 000 treatment episodes, 44.0; 95% CI, 31.0-59.2). Respiratory fluoroquinolone vs amoxicillin-based antibiotic treatment was not associated with the 5-day risk of fracture. Conclusions and relevance In this study, compared with amoxicillin-based antibiotic treatment, respiratory fluoroquinolone treatment was associated with a higher short-term risk of SCD among patients with hemodialysis-dependent kidney failure. This finding suggests that decisions between the use of respiratory fluoroquinolones and amoxicillin-based antibiotics should be individualized, with prescribers considering both the clinical benefits and potential cardiac risks. more...
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- 2021
15. Confounding in Observational Studies Evaluating the Safety and Effectiveness of Medical Treatments
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Magdalene M. Assimon
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medicine.medical_specialty ,education.field_of_study ,Clinical Research Methods ,business.industry ,Gold standard ,Confounding ,Population ,Confounding Factors, Epidemiologic ,General Medicine ,law.invention ,Randomized controlled trial ,law ,Research Design ,Health care ,medicine ,Observational study ,Risk factor ,business ,Prospective cohort study ,Intensive care medicine ,education - Abstract
Randomized controlled trials (RCTs) are considered the “gold standard” for establishing the safety and efficacy of medical treatments, such as drugs, devices, and procedures. Patients with kidney disease are often excluded from these studies (1), and it is well established that trial participants tend to be healthier than the broader kidney disease population (2). Furthermore, the number of nephrology-specific trials conducted continues to lag behind other subspecialties (3). In the absence of RCT data, nephrology practitioners may look to population-specific observational evidence to guide therapy selection. Observational studies using real-world data ( e.g. , administrative claims and electronic healthcare record data) to evaluate the safety and effectiveness of medical treatments can provide highly generalizable and valuable information to clinicians (4). However, like nonrandomized prospective cohort studies, these studies may suffer from biases that limit their validity, such as confounding. In this commentary, I describe what confounding is and provide a brief overview of common types of confounding that can arise in observational studies of medical treatments. I then highlight some common strategies for addressing confounding and discuss potential sources of residual confounding. In an observational study, confounding occurs when a risk factor for the outcome also affects the exposure of interest, either directly or indirectly. The resultant bias can strengthen, weaken, or completely reverse the true exposure-outcome association. For a factor to be a confounder, it has to be associated with both the study exposure and the study outcome, and temporally precede the exposure ( i.e. , it cannot be an intermediary factor on the causal pathway between the exposure and the outcome) (5). ### Confounding by Indication and Examples of Other Types of Confounding Confounding by indication (6) is one of the most common forms of bias present in observational studies evaluating the safety and effectiveness of medical treatments. It occurs when the clinical indication for treatment, such as the … more...
- Published
- 2021
16. Characteristics and Outcomes of Individuals With Pre-existing Kidney Disease and COVID-19 Admitted to Intensive Care Units in the United States
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Jennifer E. Flythe, Magdalene M. Assimon, Matthew J. Tugman, Emily H. Chang, Shruti Gupta, Jatan Shah, Marie Anne Sosa, Amanda DeMauro Renaghan, Michal L. Melamed, F. Perry Wilson, Javier A. Neyra, Arash Rashidi, Suzanne M. Boyle, Shuchi Anand, Marta Christov, Leslie F. Thomas, Daniel Edmonston, David E. Leaf, Carl P. Walther, Samaya J. Anumudu, Justin Arunthamakun, Kathleen F. Kopecky, Gregory P. Milligan, Peter A. McCullough, Thuy-Duyen Nguyen, Shahzad Shaefi, Megan L. Krajewski, Sidharth Shankar, Ameeka Pannu, Juan D. Valencia, Sushrut S. Waikar, Zoe A. Kibbelaar, Ambarish M. Athavale, Peter Hart, Shristi Upadhyay, Ishaan Vohra, Adam Green, Jean-Sebastien Rachoin, Christa A. Schorr, Lisa Shea, Daniel L. Edmonston, Christopher L. Mosher, Alexandre M. Shehata, Zaza Cohen, Valerie Allusson, Gabriela Bambrick-Santoyo, Noor ul aain Bhatti, Bijal Mehta, Aquino Williams, Samantha K. Brenner, Patricia Walters, Ronaldo C. Go, Keith M. Rose, Lili Chan, Kusum S. Mathews, Steven G. Coca, Deena R. Altman, Aparna Saha, Howard Soh, Huei Hsun Wen, Sonali Bose, Emily A. Leven, Jing G. Wang, Gohar Mosoyan, Girish N. Nadkarni, Pattharawin Pattharanitima, Emily J. Gallagher, Allon N. Friedman, John Guirguis, Rajat Kapoor, Christopher Meshberger, Katherine J. Kelly, Chirag R. Parikh, Brian T. Garibaldi, Celia P. Corona-Villalobos, Yumeng Wen, Steven Menez, Rubab F. Malik, Carmen Elena Cervantes, Samir C. Gautam, Mary C. Mallappallil, Jie Ouyang, Sabu John, Ernie Yap, Yohannes Melaku, Ibrahim Mohamed, Siddhartha Bajracharya, Isha Puri, Mariah Thaxton, Jyotsna Bhattacharya, John Wagner, Leon Boudourakis, H. Bryant Nguyen, Afshin Ahoubim, Kianoush Kashani, Shahrzad Tehranian, Dheeraj Reddy Sirganagari, Pramod K. Guru, Yan Zhou, Paul A. Bergl, Jesus Rodriguez, Jatan A. Shah, Mrigank S. Gupta, Princy N. Kumar, Deepa G. Lazarous, Seble G. Kassaye, Tanya S. Johns, Ryan Mocerino, Kalyan Prudhvi, Denzel Zhu, Rebecca V. Levy, Yorg Azzi, Molly Fisher, Milagros Yunes, Kaltrina Sedaliu, Ladan Golestaneh, Maureen Brogan, Neelja Kumar, Michael Chang, Jyotsana Thakkar, Ritesh Raichoudhury, Akshay Athreya, Mohamed Farag, Edward J. Schenck, Soo Jung Cho, Maria Plataki, Sergio L. Alvarez-Mulett, Luis G. Gomez-Escobar, Di Pan, Stefi Lee, Jamuna Krishnan, William Whalen, David Charytan, Ashley Macina, Sobaata Chaudhry, Benjamin Wu, Frank Modersitzki, Anand Srivastava, Alexander S. Leidner, Carlos Martinez, Jacqueline M. Kruser, Richard G. Wunderink, Alexander J. Hodakowski, Juan Carlos Q. Velez, Eboni G. Price-Haywood, Luis A. Matute-Trochez, Anna E. Hasty, Muner M.B. Mohamed, Rupali S. Avasare, David Zonies, Meghan E. Sise, Erik T. Newman, Samah Abu Omar, Kapil K. Pokharel, Shreyak Sharma, Harkarandeep Singh, Simon Correa, Tanveer Shaukat, Omer Kamal, Wei Wang, Heather Yang, Jeffery O. Boateng, Meghan Lee, Ian A. Strohbehn, Jiahua Li, Ariel L. Mueller, Roberta Redfern, Nicholas S. Cairl, Gabriel Naimy, Abeer Abu-Saif, Danyell Hall, Laura Bickley, Chris Rowan, Farah Madhani-Lovely, Vasil Peev, Jochen Reiser, John J. Byun, Andrew Vissing, Esha M. Kapania, Zoe Post, Nilam P. Patel, Joy-Marie Hermes, Anne K. Sutherland, Amee Patrawalla, Diana G. Finkel, Barbara A. Danek, Sowminya Arikapudi, Jeffrey M. Paer, Peter Cangialosi, Mark Liotta, Jared Radbel, Sonika Puri, Jag Sunderram, Matthew T. Scharf, Ayesha Ahmed, Ilya Berim, Jayanth S. Vatson, Joseph E. Levitt, Pablo Garcia, Rui Song, Jingjing Zhang, Sang Hoon Woo, Xiaoying Deng, Goni Katz-Greenberg, Katharine Senter, Moh’d A. Sharshir, Vadym V. Rusnak, Muhammad Imran Ali, Anip Bansal, Amber S. Podoll, Michel Chonchol, Sunita Sharma, Ellen L. Burnham, Rana Hejal, Eric Judd, Laura Latta, Ashita Tolwani, Timothy E. Albertson, Jason Y. Adams, Ronald Reagan, Steven Y. Chang, Rebecca M. Beutler, Santa Monica, Carl E. Schulze, Etienne Macedo, Harin Rhee, Kathleen D. Liu, Vasantha K. Jotwani, Jay L. Koyner, Alissa Kunczt, Chintan V. Shah, Vishal Jaikaransingh, Stephanie M. Toth-Manikowski, Min J. Joo, James P. Lash, Nourhan Chaaban, Rajany Dy, Alfredo Iardino, Elizabeth H. Au, Jill H. Sharma, Sabrina Taldone, Gabriel Contreras, David De La Zerda, Hayley B. Gershengorn, Salim S. Hayek, Pennelope Blakely, Hanna Berlin, Tariq U. Azam, Husam Shadid, Michael Pan, Patrick O’ Hayer, Chelsea Meloche, Rafey Feroze, Rayan Kaakati, Danny Perry, Abbas Bitar, Elizabeth Anderson, Kishan J. Padalia, John P. Donnelly, Andrew J. Admon, Brent R. Brown, Amanda K. Leonberg-Yoo, Ryan C. Spiardi, Todd A. Miano, Meaghan S. Roche, Charles R. Vasquez, Amar D. Bansal, Natalie C. Ernecoff, Sanjana Kapoor, Siddharth Verma, Huiwen Chen, Csaba P. Kovesdy, Miklos Z. Molnar, Ambreen Azhar, S. Susan Hedayati, Mridula V. Nadamuni, Shani Shastri, Duwayne L. Willett, Samuel A.P. Short, Amanda D. Renaghan, Kyle B. Enfield, Pavan K. Bhatraju, A. Bilal Malik, Matthew W. Semler, Anitha Vijayan, Christina Mariyam Joy, Tingting Li, Seth Goldberg, Patricia F. Kao, Greg L. Schumaker, Nitender Goyal, Anthony J. Faugno, Caroline M. Hsu, Asma Tariq, Leah Meyer, Ravi K. Kshirsagar, Daniel E. Weiner, Aju Jose, Jennifer Griffiths, Sanjeev Gupta, Aromma Kapoor, Perry Wilson, Tanima Arora, and Ugochukwu Ugwuowo more...
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medicine.medical_specialty ,030232 urology & nephrology ,Renal function ,Original Investigations ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Intensive care ,medicine ,critical illness ,030212 general & internal medicine ,Survival analysis ,Kidney ,business.industry ,SARS-CoV-2 ,Confounding ,COVID-19 ,Retrospective cohort study ,medicine.disease ,medicine.anatomical_structure ,Respiratory failure ,Nephrology ,end stage kidney disease ,dialysis ,business ,chronic kidney disease ,Kidney disease - Abstract
Rationale & Objective Underlying kidney disease is an emerging risk factor for more severe COVID-19 illness. We examined the clinical courses of critically ill COVID-19 patients with and without pre-existing kidney disease and investigated the association between degree of underlying kidney disease and in-hospital outcomes. Study Design Retrospective cohort study Settings & Participants 4,264 critically ill COVID-19 patients (143 dialysis patients, 521 chronic kidney disease [CKD] patients, and 3,600 patients without CKD) admitted to ICUs at 68 hospitals in the United States. Predictor(s) Presence (versus absence) of pre-existing kidney disease Outcome(s) In-hospital mortality (primary); respiratory failure, shock, ventricular arrhythmia/ cardiac arrest, thromboembolic event, major bleed, and acute liver injury (secondary) Analytical Approach We used standardized differences to compare patient characteristics (values >0.10 indicate a meaningful difference between groups) and multivariable adjusted Fine and Gray survival models to examine outcome associations. Results Dialysis patients had a shorter time from symptom onset to ICU admission compared to other groups (median [quartile 1-quartile 3] days: 4 [2-9] for dialysis patients; 7 [3-10] for CKD patients; 7 [4-10] for patients without pre-existing kidney disease). More dialysis patients (25%) reported altered mental status than those with CKD (20%, standardized difference = 0.12) and no kidney disease (12%, standardized difference = 0.36). Half of dialysis and CKD patients died within 28-days of ICU admission versus 35% of patients without pre-existing kidney disease. Compared to patients without pre-existing kidney disease, dialysis patients had a higher risk of 28-day in-hospital death (adjusted HR 1.41; 95% CI 1.09, 1.81), while patients with CKD had an intermediate risk (adjusted HR 1.25; 95% CI 1.08, 1.44). Limitations Potential residual confounding Conclusions Findings highlight the high mortality of individuals with underlying kidney disease and severe COVID-19, underscoring the importance of identifying safe and effective COVID-19 therapies for this vulnerable population., Individuals with underlying kidney disease may be particularly vulnerable to severe COVID-19 illness, marked by multi-system organ failure, thrombosis, and a heightened inflammatory response. Among 4,264 critically ill adults with COVID-19 admitted to 68 intensive care units across the U.S., we found that both chronic kidney disease and dialysis patients had a ∼50% 28-day in-hospital mortality rate. Patients with underlying kidney disease had higher in-hospital mortality than patients without kidney disease, with patients on maintenance dialysis having the highest risk. As evidenced by differences in symptoms and clinical trajectories, patients with pre-existing kidney disease may have unique susceptibility to COVID-19-related complications which warrants additional study and special consideration in the pursuit and development of targeted therapies. more...
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- 2021
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17. Effect of ultrafiltration profiling on outcomes among maintenance hemodialysis patients: a pilot randomized crossover trial
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Steven M. Brunelli, Alan L. Hinderliter, Quefeng Li, Magdalene M. Assimon, Yueting Wang, Matthew J. Tugman, Jennifer E. Flythe, and Julia H. Narendra
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Male ,medicine.medical_treatment ,030232 urology & nephrology ,Hemodynamics ,Ultrafiltration ,Blood volume ,Pilot Projects ,030204 cardiovascular system & hematology ,Article ,03 medical and health sciences ,0302 clinical medicine ,Renal Dialysis ,medicine ,Intravascular volume status ,Humans ,Cross-Over Studies ,Troponin T ,business.industry ,Sodium ,Infant, Newborn ,medicine.disease ,Crossover study ,Blood pressure ,Nephrology ,Anesthesia ,Female ,Hemodialysis ,Hypotension ,Hypervolemia ,business - Abstract
BACKGROUND: More rapid fluid removal during hemodialysis is associated with adverse cardiovascular outcomes and longer dialysis recovery times. The effect of ultrafiltration (UF) profiling, independent of concomitant sodium profiling, on markers of intradialytic hemodynamics and other outcomes has been inadequately studied. METHODS: Four-phase, blinded crossover trial. Participants (UF rates >10 mL/h/kg) were assigned in random order to receive hemodialysis with UF profiling (constantly declining UF rate, intervention) vs. hemodialysis with conventional UF (control). Each 3-week 9-treatment period was followed by a 1-week 3-treatment washout period. Participants crossed into each study arm twice (2 phases/arm); 18 treatments per treatment type. The primary outcomes were intradialytic hypotension, pre- to post-dialysis troponin T change, and change from baseline in left ventricular global longitudinal strain. Other outcomes included intradialytic symptoms and blood volume measured-plasma refill (post-dialysis volume status measure), among others. Each participant served as their own control. RESULTS: On average, the 34 randomized patients (mean age 56 years, 24% female, mean dialysis vintage 6.3 years) had UF rates >10 mL/h/kg in 56% of treatments during the screening period. All but 2 patients completed the 15-week study (prolonged hospitalization, kidney transplant). There was no significant difference in intradialytic hypotension, troponin T change, or left ventricular strain between hemodialysis with UF profiling and conventional UF. With UF profiling, participants had significantly lower odds of light-headedness and plasma refill compared to hemodialysis with conventional UF. CONCLUSIONS: UF profiling did not reduce the odds of treatment-related cardiac stress but did reduce the odds of light-headedness and post-dialysis hypervolemia. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT03301740 (registered October 4, 2017) more...
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- 2020
18. Use of QT Prolonging Medications by Hemodialysis Patients and Individuals Without End‐Stage Kidney Disease
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Wolfgang C. Winkelmayer, Lily Wang, Magdalene M. Assimon, Patrick H. Pun, and Jennifer E. Flythe
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patterns of use ,Male ,medicine.medical_specialty ,Time Factors ,Databases, Factual ,Epidemiology ,medicine.medical_treatment ,Population ,030232 urology & nephrology ,Comorbidity ,Arrhythmias ,030204 cardiovascular system & hematology ,Medicare ,Risk Assessment ,Sudden cardiac death ,03 medical and health sciences ,0302 clinical medicine ,Renal Dialysis ,Risk Factors ,Torsades de Pointes ,Internal medicine ,QT prolonging medications ,medicine ,Humans ,End-stage kidney disease ,education ,Original Research ,Aged ,Retrospective Studies ,Aged, 80 and over ,education.field_of_study ,business.industry ,Middle Aged ,medicine.disease ,Drug Utilization ,United States ,Death, Sudden, Cardiac ,Hemodialysis ,Polypharmacy ,Cardiology ,Kidney Failure, Chronic ,Female ,Cardiology and Cardiovascular Medicine ,business - Abstract
Background The rate of sudden cardiac death in the hemodialysis population exceeds that of the general population by >20‐fold. Hemodialysis patients may be particularly susceptible to sudden cardiac death provoked by drug‐induced QT prolongation because of their substantial cardiovascular disease burden, exposure to electrolyte shifts during dialysis, and extensive polypharmacy. However, population‐specific data regarding the frequency and patterns of QT prolonging medication use are limited. Methods and Results We conducted a descriptive drug utilization study using 3 administrative databases, the United States Renal Data System, MarketScan, and Medicare claims. We characterized the extent and patterns of QT prolonging medication use by adult hemodialysis patients and individuals without end‐stage kidney disease annually from 2012 to 2016. We also identified instances of high‐risk QT prolonging medication use among hemodialysis patients. In total, 338 515 hemodialysis patients and 40.7 million individuals without end‐stage kidney disease were studied. Annual utilization rates of QT prolonging medications with known torsades de pointes risk in hemodialysis patients were ~1.4 to ~2.5 times higher than utilization rates in individuals without end‐stage kidney disease. Hemodialysis patients with demographic and clinical risk factors for drug‐induced QT prolongation were exposed to medications with known torsades de pointes risk more often than patients without risk factors. Conclusions Hemodialysis patients use QT prolonging medications with known torsades de pointes risk more extensively than individuals without end‐stage kidney disease. Given the widespread use and instances of high‐risk prescribing, future studies evaluating the cardiac safety of these drugs in the hemodialysis population are needed. more...
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- 2020
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19. Feasibility of Tablet-Based Patient-Reported Symptom Data Collection Among Hemodialysis Patients
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Julia H. Narendra, Magdalene M. Assimon, Adeline Dorough, Jennifer E. Flythe, Johnathan Hilbert, Darren A. DeWalt, and Matthew J. Tugman
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medicine.medical_specialty ,Quality management ,mixed methods ,medicine.medical_treatment ,030232 urology & nephrology ,030204 cardiovascular system & hematology ,lcsh:RC870-923 ,03 medical and health sciences ,0302 clinical medicine ,Clinical Research ,medicine ,EPROM ,implementation ,improvement ,Data collection ,hemodialysis ,business.industry ,Outcome measures ,Usability ,lcsh:Diseases of the genitourinary system. Urology ,Nephrology ,patient-reported outcomes ,quality ,Physical therapy ,symptoms ,Hemodialysis ,business - Abstract
Introduction Individuals receiving in-center hemodialysis have high symptom burdens but often do not report their symptoms to care teams. Evidence from other diseases suggest that use of symptom electronic patient-reported outcome measures (ePROMs) may improve outcomes. We assessed the usability of a symptom ePROM system and then implemented a quality improvement (QI) project with the objective of improving symptom communication at a US hemodialysis clinic. During the project, we assessed the feasibility of ePROM implementation and conducted a substudy exploring the effect of ePROM use on patient-centered care. Methods After conducting usability testing, we used mixed methods, guided by the Quality Implementation Framework, to implement a 16-week symptom ePROM QI project. We performed pre-, intra-, and postproject stakeholder interviews to identify implementation barriers and facilitators. We collected ePROM system-generated data on symptoms, e-mail alerts, and response rates, among other factors, to inform our feasibility assessment. We compared pre- and postproject outcomes. Results There were 62 patient participants (34% black, 16% Spanish-speaking) and 19 care team participants (4 physicians, 15 clinic personnel) at QI project start, and 32 research participants. In total, the symptom ePROM was administered 496 times (completion rate = 84%). The implementation approach and ePROM system were modified to address stakeholder-identified concerns throughout. ePROM implementation was feasible as demonstrated by the program’s acceptability, demand, implementation success, practicality, integration in care, and observed trend toward improved outcomes. Conclusions Symptom ePROM administration during hemodialysis is feasible. Trials investigating the effectiveness of symptom ePROMs and optimal administration strategies are needed., Graphical abstract more...
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- 2020
20. A Comparative Study of Carvedilol Versus Metoprolol Initiation and 1-Year Mortality Among Individuals Receiving Maintenance Hemodialysis
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Magdalene M. Assimon, Jason P. Fine, Gerardo Heiss, Jennifer E. Flythe, J. Bradley Layton, and M. Alan Brookhart
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Male ,medicine.medical_specialty ,Time Factors ,medicine.drug_class ,medicine.medical_treatment ,Population ,030232 urology & nephrology ,030204 cardiovascular system & hematology ,Cohort Studies ,03 medical and health sciences ,0302 clinical medicine ,Renal Dialysis ,Internal medicine ,medicine ,Humans ,Mortality ,Renal Insufficiency, Chronic ,education ,Beta blocker ,Carvedilol ,Dialysis ,Aged ,Retrospective Studies ,Metoprolol ,education.field_of_study ,business.industry ,Retrospective cohort study ,Middle Aged ,Adrenergic beta-1 Receptor Antagonists ,Blood pressure ,Nephrology ,Cardiology ,Female ,Hemodialysis ,business ,medicine.drug - Abstract
Background Carvedilol and metoprolol are the β-blockers most commonly prescribed to US hemodialysis patients, accounting for ∼80% of β-blocker prescriptions. Despite well-established pharmacologic and pharmacokinetic differences between the 2 medications, little is known about their relative safety and efficacy in the hemodialysis population. Study Design A retrospective cohort study using a new-user design. Setting & Participants Medicare-enrolled hemodialysis patients treated at a large US dialysis organization who initiated carvedilol or metoprolol therapy from January 1, 2007, through December 30, 2012. Predictor Carvedilol versus metoprolol initiation. Outcomes All-cause mortality, cardiovascular mortality, and intradialytic hypotension (systolic blood pressure decrease ≥ 20mmHg during hemodialysis plus intradialytic saline solution administration) during a 1-year follow-up period. Measurements Survival models were used to estimate HRs and 95% CIs in mortality analyses. Poisson regression was used to estimate incidence rate ratios (IRRs) and 95% CIs in intradialytic hypotension analyses. Inverse probability of treatment weighting was used to adjust for several demographic, clinical, laboratory, and dialysis treatment covariates in all analyses. Results 27,064 individuals receiving maintenance hemodialysis were included: 9,558 (35.3%) carvedilol initiators and 17,506 (64.7%) metoprolol initiators. Carvedilol (vs metoprolol) initiation was associated with greater all-cause (adjusted HR, 1.08; 95% CI, 1.02-1.16) and cardiovascular mortality (adjusted HR, 1.18; 95% CI, 1.08-1.29). In subgroup analyses, similar associations were observed among patients with hypertension, atrial fibrillation, heart failure, and a recent myocardial infarction, the main cardiovascular indications for β-blocker therapy. During follow-up, carvedilol (vs metoprolol) initiators had a higher rate of intradialytic hypotension (adjusted IRR, 1.10; 95% CI, 1.09-1.11). Limitations Residual confounding may exist. Conclusions Relative to metoprolol initiation, carvedilol initiation was associated with higher 1-year all-cause and cardiovascular mortality. One potential mechanism for these findings may be the increased occurrence of intradialytic hypotension after carvedilol (vs metoprolol) initiation. more...
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- 2018
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21. Intradialytic Hypertension Frequency and Short-Term Clinical Outcomes Among Individuals Receiving Maintenance Hemodialysis
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Jennifer E. Flythe, Magdalene M. Assimon, and Lily Wang
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Adult ,Male ,medicine.medical_specialty ,Time Factors ,Databases, Factual ,Original Contributions ,medicine.medical_treatment ,Population ,030232 urology & nephrology ,Blood Pressure ,030204 cardiovascular system & hematology ,03 medical and health sciences ,0302 clinical medicine ,Recurrence ,Renal Dialysis ,Risk Factors ,Internal medicine ,Internal Medicine ,Humans ,Medicine ,education ,Dialysis ,Aged ,Retrospective Studies ,education.field_of_study ,business.industry ,Hazard ratio ,Retrospective cohort study ,Middle Aged ,United States ,Confidence interval ,Hospitalization ,Treatment Outcome ,Blood pressure ,Hypertension ,Cohort ,Kidney Failure, Chronic ,Female ,Hemodialysis ,business - Abstract
BACKGROUND Intradialytic hypertension occurs in 5–20% of hemodialysis treatments. Observational data support an association between intradialytic hypertension and long-term mortality. However, the short-term consequences of recurrent intradialytic hypertension are unknown. METHODS Data were taken from a cohort of prevalent hemodialysis patients receiving treatment at a large United States dialysis organization on 1 January 2010. A retrospective cohort design with a 180-day baseline, 30-day exposure assessment, and 30-day follow-up period was used to estimate the associations between intradialytic hypertension frequency and 30-day outcomes. Intradialytic hypertension frequency was defined as the proportion of exposure period hemodialysis treatments with a predialysis to postdialysis systolic blood pressure rise >0 mm Hg. Multivariable Cox proportional hazards regression, adjusted for baseline clinical, laboratory, and dialysis treatment covariates, was used to estimate hazard ratios and 95% confidence intervals. RESULTS Of the 37,094 study patients, 5,242 (14.1%), 17,965 (48.4%), 10,821 (29.2%), 3,066 (8.3%) had intradialytic hypertension in 0%, 1–32%, 33–66%, and ≥67% of exposure period treatments, respectively. More frequent intradialytic hypertension was associated with incremental increases in 30-day mortality and hospitalizations. Patients with intradialytic hypertension in ≥67% (vs. 0%) of exposure period treatments had the highest risk of all-cause death, hazard ratio [95% confidence interval]: 2.57 [1.68, 3.94]; cardiovascular (CV) death, 3.68 [1.89, 7.15]; all-cause hospitalizations, 1.42 [1.26, 1.62]; CV hospitalizations, 1.71 [1.36, 2.15]; and volume-related hospitalizations, 2.25 [1.25, 4.04]. CONCLUSIONS Among prevalent hemodialysis patients, more frequent intradialytic hypertension was incrementally associated with increased 30-day morbidity and mortality. Intradialytic hypertension may be an important short-term risk marker in the hemodialysis population. more...
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- 2017
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22. Definitions of intradialytic hypotension
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Jennifer E. Flythe and Magdalene M. Assimon
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medicine.medical_specialty ,education.field_of_study ,business.industry ,Data synthesis ,medicine.medical_treatment ,Population ,030232 urology & nephrology ,Psychological intervention ,MEDLINE ,030204 cardiovascular system & hematology ,Surgery ,03 medical and health sciences ,0302 clinical medicine ,Blood pressure ,Nephrology ,medicine ,Clinical significance ,Hemodialysis ,Intradialytic hypotension ,education ,business ,Intensive care medicine - Abstract
Intradialytic hypotension (IDH) is a common and often distressful complication of hemodialysis. However, despite its clinical significance, there is no consensus, evidence-based medical definition for the condition. Over the years, numerous definitions have been implemented in both the clinical and research settings. Definition inconsistencies have hindered data synthesis and the development of evidence-based guidelines for the prevention and treatment of IDH, as well as prevented accurate estimation of the population burden of IDH and patient risk assessment. Most existing IDH definitions are comprised of one or more of the following components: (1) intradialytic BP criteria (requisite BP declines or minimum BP thresholds), (2) the provision of interventions aimed at restoring effective arterial volume, and/or (3) patient-reported symptoms. Remarkably, there are insufficient data to inform IDH definition construction, and it remains unknown if a single, universal definition can adequately capture the condition across patient subgroups, and in clinical and research settings. more...
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- 2017
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23. Ultrafiltration Rate and Residual Kidney Function Decline: Yet Another Good Reason to Ask About Urine
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Jennifer E. Flythe and Magdalene M. Assimon
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medicine.medical_specialty ,business.industry ,Extramural ,medicine.medical_treatment ,Ultrafiltration ,Urology ,Renal function ,Urine ,Article ,Peritoneal dialysis ,Nephrology ,Renal Dialysis ,Medicine ,Humans ,business ,Peritoneal Dialysis - Abstract
RATIONALE & OBJECTIVE: Patients receiving twice-weekly or less-frequent hemodialysis (HD) may need to undergo higher ultrafiltration rates (UFRs) to maintain acceptable fluid balance. We hypothesized that higher UFRs are associated with faster decline in residual kidney function (RKF) and a higher rate of mortality. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 1,524 patients with kidney failure who initiated maintenance HD at a frequency of twice or less per week for at least 6 consecutive weeks at some time between 2007 and 2011 and for whom baseline data for UFR and renal urea clearance were available. PREDICTOR: Average UFR during the first patient-quarter during less-frequent HD ( more...
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- 2019
24. Comparative Cardiac Safety of Selective Serotonin Reuptake Inhibitors among Individuals Receiving Maintenance Hemodialysis
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M. Alan Brookhart, Magdalene M. Assimon, and Jennifer E. Flythe
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medicine.medical_specialty ,Maintenance ,medicine.medical_treatment ,030232 urology & nephrology ,030204 cardiovascular system & hematology ,Citalopram ,QT interval ,behavioral disciplines and activities ,Sudden cardiac death ,03 medical and health sciences ,Electrocardiography ,0302 clinical medicine ,Renal Dialysis ,Internal medicine ,mental disorders ,medicine ,Escitalopram ,Humans ,Clinical Epidemiology ,Sertraline ,Fluoxetine ,business.industry ,Hazard ratio ,General Medicine ,medicine.disease ,Death, Sudden, Cardiac ,Nephrology ,Hemodialysis ,Safety ,business ,Selective Serotonin Reuptake Inhibitors ,medicine.drug - Abstract
Background Individuals receiving maintenance hemodialysis may be particularly susceptible to the lethal cardiac consequences of drug-induced QT prolongation because they have a substantial cardiovascular disease burden and high level of polypharmacy, as well as recurrent exposure to electrolyte shifts during dialysis. Electrophysiologic data indicate that among the selective serotonin reuptake inhibitors (SSRIs), citalopram and escitalopram prolong the QT interval to the greatest extent. However, the relative cardiac safety of SSRIs in the hemodialysis population is unknown. Methods In this retrospective cohort study, we used data from a cohort of Medicare beneficiaries receiving hemodialysis included in the US Renal Data System registry (2007–2014). We used a new-user design to compare the 1-year risk of sudden cardiac death among hemodialysis patients initiating SSRIs with a higher potential for prolonging the QT interval (citalopram, escitalopram) versus the risk among those initiating SSRIs with lower QT-prolonging potential (fluoxetine, fluvoxamine, paroxetine, sertraline). We estimated adjusted hazard ratios using inverse probability of treatment weighted survival models. Nonsudden cardiac death was treated as a competing event. Results The study included 30,932 (47.1%) hemodialysis patients who initiated SSRIs with higher QT-prolonging potential and 34,722 (52.9%) who initiated SSRIs with lower QT-prolonging potential. Initiation of an SSRI with higher versus lower QT-prolonging potential was associated with higher risk of sudden cardiac death (adjusted hazard ratio, 1.18; 95% confidence interval, 1.05 to 1.31). This association was more pronounced among elderly individuals, females, patients with conduction disorders, and those treated with other non-SSRI QT-prolonging medications. Conclusions The heterogeneous QT-prolonging potential of SSRIs may differentially affect cardiac outcomes in the hemodialysis population. more...
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- 2019
25. Variability May Be the 'Law of Life,' but Blood Pressure Variability May Forebode a Shorter Life
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Magdalene M. Assimon and Jennifer E. Flythe
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medicine.medical_specialty ,Kidney ,business.industry ,Disease ,030204 cardiovascular system & hematology ,medicine.disease ,Surgery ,03 medical and health sciences ,0302 clinical medicine ,Blood pressure ,medicine.anatomical_structure ,Nephrology ,Internal medicine ,Ambulatory ,medicine ,Cardiology ,Myocardial infarction ,Risk factor ,business ,Stroke ,030217 neurology & neurosurgery ,Kidney disease - Abstract
Genetic, phenotypic, and physiologic variability complicate the understanding, diagnosis, and treatment of almost all disease states. Historically, blood pressure (BP) variations across clinic visits were viewed as random fluctuations without clinical or prognostic significance. However, emerging evidence suggests that these long-term fluctuations, termed BP visit-to-visit variability, portend a range of adverse health events in the general and kidney disease populations. 2-4 Higher BP visit-to-visit variability has been associated with acute myocardial infarction (MI), stroke, and left ventricular dysfunction. 5 Such adverse clinical outcomes have proved particularly difficult to modify among patients with chronic kidney disease due to the complex interplay of traditional and kidney disease–specific risk factors involved in cardiovascular disease pathogenesis. The prospect of long-term BP visit-to-visit variability as a novel modifiable cardiovascular risk factor has generated enthusiasm among some because it potentially represents a new therapeutic target through which to improve patient outcomes. more...
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- 2016
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26. Thirty-Day Hospital Readmissions in the Hemodialysis Population
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Magdalene M. Assimon and Jennifer E. Flythe
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medicine.medical_specialty ,Epidemiology ,John dewey ,medicine.medical_treatment ,Population ,030232 urology & nephrology ,030204 cardiovascular system & hematology ,Critical Care and Intensive Care Medicine ,03 medical and health sciences ,0302 clinical medicine ,THIRTY-DAY ,Medicine ,education ,health care economics and organizations ,Transplantation ,education.field_of_study ,Hospital readmission ,business.industry ,Editorials ,medicine.disease ,humanities ,Nephrology ,Emergency medicine ,Medicare population ,Hemodialysis ,Medical emergency ,business - Abstract
> “A problem well put is half-solved” > > (John Dewey, 1859–1952). In recent years, United States policymakers have made 30-day hospital readmission reduction a centerpiece of efforts to curb Medicare costs. In the general Medicare population, 15% of patients are readmitted to the hospital more...
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- 2017
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27. Cumulative Exposure to Frequent Intradialytic Hypotension Associates With New-Onset Dementia Among Elderly Hemodialysis Patients
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Magdalene M. Assimon, Lily Wang, and Jennifer E. Flythe
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medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,030232 urology & nephrology ,MEDLINE ,Cumulative Exposure ,030204 cardiovascular system & hematology ,medicine.disease ,New onset ,03 medical and health sciences ,0302 clinical medicine ,Nephrology ,Internal medicine ,Research Letter ,Medicine ,Dementia ,Hemodialysis ,Intradialytic hypotension ,business - Published
- 2018
28. Ultrafiltration rate scaling in hemodialysis patients
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Magdalene M. Assimon, Jennifer E. Flythe, and Lily Wang
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Male ,Chromatography ,business.industry ,medicine.medical_treatment ,030232 urology & nephrology ,Ultrafiltration ,030204 cardiovascular system & hematology ,Article ,03 medical and health sciences ,0302 clinical medicine ,Nephrology ,Renal Dialysis ,Medicine ,Humans ,Kidney Failure, Chronic ,Female ,Hemodialysis ,business - Published
- 2017
29. Observation stays in administrative claims databases: underestimation of hospitalized cases
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Robert A. Overman, Magdalene M. Assimon, M. Alan Brookhart, Janet K. Freburger, and Xiaojuan Li
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Potential impact ,Database ,Epidemiology ,business.industry ,Patient demographics ,Pharmacoepidemiology ,computer.software_genre ,medicine.disease ,Administrative claims ,Inpatient stays ,Medicine ,Pharmacology (medical) ,In patient ,Diagnosis code ,Medical emergency ,business ,Healthcare data ,computer - Abstract
Purpose Recent policy changes in the USA have led to an increasing number of patients being placed into observation units rather than admitted directly to the hospital. Studies of administrative data that use inpatient diagnosis codes to identify cohorts, outcomes, or covariates may be affected by this change in practice. To understand the potential impact of observation stays on research using administrative healthcare data, we examine the trends of observation stays, short (≤2 days) inpatient admissions, and all inpatient admissions. Methods We examined a large administrative claims database of commercially insured individuals in the USA between 2002 and 2011. Observation stays were defined on the basis of the procedure codes reimbursable by Medicare or commercial insurers. We report monthly rates of observation stays and short inpatient admissions overall and by patient demographics. Results We identified 5 355 752 observation stays from 2002 to 2011. Over the course of study, the rate of observation stays increased, whereas the rate of short inpatient stays declined. The most common reason for observation stays was nonspecific chest pain, also the third most common reason for short inpatient stays. The increasing trend of observation stays related to circulatory diseases mirrors the decreasing trend of short inpatient stays. Conclusions The use of observation stays has increased in patients with commercial insurance. Failure to account for observation stays may lead to an under-ascertainment of hospitalizations in contemporary administrative healthcare data from the USA. Copyright © 2014 John Wiley & Sons, Ltd. more...
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- 2014
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30. Ultrafiltration Rate and Mortality in Maintenance Hemodialysis Patients
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Jennifer E. Flythe, Julia Wenger, Lily Wang, and Magdalene M. Assimon
- Subjects
Male ,medicine.medical_specialty ,medicine.medical_treatment ,030232 urology & nephrology ,Ultrafiltration ,030204 cardiovascular system & hematology ,Article ,03 medical and health sciences ,0302 clinical medicine ,Renal Dialysis ,Internal medicine ,Medicine ,Humans ,Body Weights and Measures ,Dialysis ,Retrospective Studies ,Body surface area ,business.industry ,Mortality rate ,Confounding ,Anthropometry ,Middle Aged ,Surgery ,Nephrology ,Female ,Hemodialysis ,business ,Body mass index - Abstract
Background Observational data have demonstrated an association between higher ultrafiltration rates and greater mortality among hemodialysis patients. Prior studies were small and did not consider potential differences in the association across body sizes and other related subgroups. No study has investigated ultrafiltration rates normalized to anthropometric measures beyond body weight. Also, potential methodological shortcomings in prior studies have led to questions about the veracity of the ultrafiltration rate−mortality association. Study Design Retrospective cohort. Setting & Participants 118,394 hemodialysis patients dialyzing in a large dialysis organization, 2008 to 2012. Predictors Mean 30-day ultrafiltration rates were dichotomized at 13 and 10mL/h/kg, separately and categorized using various cutoff points. Ultrafiltration rates normalized to body weight, body mass index, and body surface area were investigated. Outcomes All-cause mortality. Measurements Multivariable survival models were used to estimate the association between ultrafiltration rate and all-cause mortality. Results At baseline, 21,735 (18.4%) individuals had ultrafiltration rates > 13mL/h/kg and 48,529 (41.0%) had ultrafiltration rates > 10mL/h/kg. Median follow-up was 2.3 years, and the mortality rate was 15.3 deaths/100 patient-years. Compared with ultrafiltration rates ≤ 13mL/h/kg, ultrafiltration rates > 13mL/h/kg were associated with greater mortality (adjusted HR, 1.31; 95% CI, 1.28-1.34). Compared with ultrafiltration rates ≤ 10mL/h/kg, ultrafiltration rates > 10mL/h/kg were associated with greater mortality (adjusted HR, 1.22; 95% CI, 1.20-1.24). Findings were consistent across subgroups of sex, race, dialysis vintage, session duration, and body size. Higher ultrafiltration rates were associated with greater mortality when normalized to body weight, body mass index, and body surface area. Limitations Residual confounding cannot be excluded given the observational study design. Conclusions Regardless of the threshold implemented, higher ultrafiltration rate was associated with greater mortality in the overall study population and across key subgroups. Randomized controlled trials are needed to investigate whether ultrafiltration rate reduction improves clinical outcomes. more...
- Published
- 2016
31. Ultrafiltration Rates and the Quality Incentive Program: Proposed Measure Definitions and Their Potential Dialysis Facility Implications
- Author
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Lily Wang, Julia Wenger, Magdalene M. Assimon, and Jennifer E. Flythe
- Subjects
Adult ,medicine.medical_specialty ,Time Factors ,Quality Assurance, Health Care ,Epidemiology ,medicine.medical_treatment ,media_common.quotation_subject ,030232 urology & nephrology ,Ultrafiltration ,Hemodiafiltration ,030204 cardiovascular system & hematology ,Critical Care and Intensive Care Medicine ,Ambulatory Care Facilities ,Centers for Medicare and Medicaid Services, U.S ,03 medical and health sciences ,0302 clinical medicine ,Sex Factors ,medicine ,Humans ,Quality (business) ,Prospective cohort study ,Dialysis facility ,Dialysis ,media_common ,Aged ,Quality Indicators, Health Care ,Transplantation ,Kilogram ,business.industry ,Body Weight ,Age Factors ,Editorials ,Hispanic or Latino ,Middle Aged ,United States ,Black or African American ,Nephrology ,Emergency medicine ,Hemodialysis ,Seasons ,business ,Medicaid - Abstract
Background and objectives Rapid ultrafiltration rates are associated with adverse outcomes among patients on hemodialysis. The Centers for Medicare and Medicaid Services is considering an ultrafiltration rate quality measure for the ESRD Quality Incentive Program. Two measure developers proposed ultrafiltration rate measures with different selection criteria and specifications. We aimed to compare the proposed ultrafiltration rate measures and quantify dialysis facility operational burden if treatment times were extended to lower ultrafiltration rates. Design, setting, participants, & measurements Data were taken from the 2012 database of a large dialysis organization. Analyses of the Centers for Medicare and Medicaid Services measure considered 148,950 patients on hemodialysis, and analyses of the Kidney Care Quality Alliance measure considered 151,937 patients. We described monthly patient and facility ultrafiltration rates and examined differences in patient characteristics across ultrafiltration rate thresholds and differences in facilities across ultrafiltration rate measure scores. We computed the additional treatment time required to lower ultrafiltration rates Results Ultrafiltration rates peaked in winter and nadired in summer. Patients with higher ultrafiltration rates were younger; more likely to be women, nonblack, Hispanic, and lighter in weight; and more likely to have histories of heart failure compared with patients with lower ultrafiltration rates. Facilities had, on average, 20.8%±10.3% (July) to 22.8%±10.6% (February) of patients with ultrafiltration rates >13 ml/h per kilogram by the Centers for Medicare and Medicaid Services monthly measure. Facilities had, on average, 15.8%±8.2% of patients with ultrafiltration rates ≥13 ml/h per kilogram by the Kidney Care Quality Alliance annual measure. Larger facilities (>100 patients) would require, on average, 33 additional treatment hours per week to lower all facility ultrafiltration rates Conclusions Ultrafiltration rates vary seasonally and across clinical subgroups. Extension of treatment time as a strategy to lower ultrafiltration rates may pose facility operational challenges. Prospective studies of ultrafiltration rate threshold implementation are needed. more...
- Published
- 2016
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32. Nervous system autoantibodies and vitamin D receptor gene polymorphisms in hemodialysis patients
- Author
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Magdalene M. Assimon, Jeffrey R. Bishop, Hassan A. N. El-Fawal, and Darius L. Mason
- Subjects
medicine.medical_specialty ,Glial fibrillary acidic protein ,biology ,business.industry ,Autoantibody ,Hematology ,medicine.disease ,Calcitriol receptor ,vitamin D deficiency ,FokI ,Myelin basic protein ,Ergocalciferol ,Endocrinology ,Nephrology ,Internal medicine ,Immunology ,medicine ,biology.protein ,Vitamin D and neurology ,business ,medicine.drug - Abstract
Cognitive deficits are prevalent in hemodialysis (HD) patients. Vitamin D deficiency and vitamin D receptor (VDR) gene single nucleotide polymorphism (SNPs) have been linked to both neurodegeneration (ND) and neuroprotection, respectively. Autoantibodies (Ab) to myelin basic protein (MBP), glial fibrillary acidic protein (GFAP), and neurofilament (NF) triplet proteins arise secondary to nervous system (NS) damage providing a means to assess neurological injury. Characterization of Ab biomarkers of NS damage in HD patients, their association with VDR SNPs, and nutritional vitamin D (NVD) therapy was performed. VDR genotypes, cytokines, and Ab biomarkers to NS proteins in HD subjects receiving ergocalciferol (n = 40) were compared with nonusers (n = 71). Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and immunoglobulin G (IgG) titers against NFs, GFAP, and MBP were measured by immunoassay. Subjects were genotyped for VDR SNPs BsmI (rs1544410) and FokI (rs2228570). Subjects (age 63.3 ± 16.1 years, 66% male) who were C allele carriers of BsmI had higher values of NF-68 antibody titers (p = 0.027). Ergocalciferol users (n = 40) compared with nonusers (n = 71) had lower Ab titers to NS proteins; however, only anti-NF-160 and anti-MBP titers were significantly (p < 0.05) higher. IgG against NS proteins in HD patients suggests neuronal and glial insult and a relationship with VDR alleles. NVD may provide some neuroprotection, indicated by anti-NF-160 and anti-MBP, which was markedly lowered in ergocalciferol patients. This preliminary study suggests that Ab detection may be useful in monitoring ND and the potential of NVD for neuroprotection in HD patients. more...
- Published
- 2012
- Full Text
- View/download PDF
33. Rapid ultrafiltration rates and outcomes among hemodialysis patients: re-examining the evidence base
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Magdalene M. Assimon and Jennifer E. Flythe
- Subjects
Risk ,medicine.medical_specialty ,medicine.medical_treatment ,MEDLINE ,Ultrafiltration ,Fluid management ,Weight Gain ,Article ,Ischemia ,Renal Dialysis ,Internal Medicine ,medicine ,Intravascular volume status ,Animals ,Humans ,Intensive care medicine ,Blood Volume ,business.industry ,Extramural ,Maintenance hemodialysis ,Surgery ,Clinical trial ,Nephrology ,Observational study ,Hemodialysis ,business - Abstract
This review critically summarizes the evidence linking ultrafiltration rates to adverse outcomes among hemodialysis patients and provides research recommendations to address knowledge gaps.Growing evidence suggests that fluid-related factors play important roles in hemodialysis patient outcomes. Ultrafiltration rate - the rate of fluid removal during hemodialysis - is one such factor. Existing observational data suggest a robust association between greater ultrafiltration rates and adverse cardiovascular outcomes, and such findings are supported by plausible physiologic rationale. Potential mechanistic pathways include ultrafiltration-related ischemia to the heart, brain, and gut, and volume overload-precipitated cardiac stress from reactive measures to ultrafiltration-induced hemodynamic instability. Inter-relationships among ultrafiltration rates and other fluid measures, such as interdialytic weight gain and chronic volume expansion, render the specific role of ultrafiltration rates in adverse outcomes difficult to study. Randomized trials must be conducted to confirm epidemiologic findings and examine the effect of ultrafiltration rate reduction on clinical and patient-centered outcomes.Compelling observational data demonstrate an association between more rapid ultrafiltration rates and adverse clinical outcomes. Before translating these findings into clinical practice, randomized trials are needed to verify observational data results and to identify effective strategies to mitigate ultrafiltration-related risk. more...
- Published
- 2015
34. Intradialytic blood pressure abnormalities: the highs, the lows, and all that lies between
- Author
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Jennifer E. Flythe and Magdalene M. Assimon
- Subjects
medicine.medical_specialty ,medicine.medical_treatment ,030232 urology & nephrology ,Blood Pressure ,030204 cardiovascular system & hematology ,Article ,03 medical and health sciences ,Patient safety ,0302 clinical medicine ,Renal Dialysis ,medicine ,Humans ,Prospective Studies ,Hypertension diagnosis ,Intensive care medicine ,Prospective cohort study ,business.industry ,Optimal management ,3. Good health ,Blood pressure ,Nephrology ,Hypertension ,Observational study ,Hemodialysis ,Intradialytic hypotension ,Hypotension ,business - Abstract
Background: Frequent blood pressure (BP) measurements are necessary to ensure patient safety during hemodialysis treatments. Intradialytic BPs are not optimal tools for hypertension diagnosis and cardiovascular risk stratification, but they do have critical clinical and prognostic significance. We present evidence associating intradialytic BP phenomena including fall, rise and variability with adverse clinical outcomes and review related pathophysiologic mechanisms and potential management strategies. Summary: Observational studies demonstrate associations between intradialytic hypotension, hypertension and BP variability and mortality. Lack of consensus regarding diagnostic criteria has hampered data synthesis, and prospective studies investigating optimal management strategies for BP phenomena are lacking. Mechanistic data suggest that cardiac, gut, kidney and brain ischemia may lie on the causal pathway between intradialytic hypotension and mortality, and endothelial cell dysfunction, among other factors, may be an important mediator of intradialytic hypertension and adverse outcomes. These plausible pathophysiologic links present potential therapeutic targets for future inquiry. The phenomenon of intradialytic BP variability has not been adequately studied, and practical clinical measures and treatment strategies are lacking. Key Messages: Intradialytic BP phenomena have important prognostic bearing. Clinical practice guidelines for both intradialytic hypotension and hypertension exist, but their underlying evidence is weak overall. Further research is needed to develop consensus diagnostic criteria for intradialytic hypotension, hypertension and BP variability and to elucidate optimal treatment and prevention strategies for each BP manifestation. more...
- Published
- 2015
35. Abstract P374: Monthly distribution of incident myocardial infarction in four United States communities: the Atherosclerosis Risk in Communities Study
- Author
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Magdalene M Assimon, Eunsil Yim, Lisa Wruck, Larisa G Tereshchenko, and Wayne D Rosamond
- Subjects
Physiology (medical) ,Cardiology and Cardiovascular Medicine - Abstract
Background: A seasonal periodicity, winter peaks and summer troughs, of coronary heart disease (CHD) mortality has been identified by several investigations in various parts of the world using vital statistics. However, population-based studies describing seasonal patterns of validated incident non-fatal and fatal myocardial infarction (MI) are sparse. Thus, we aim to characterize the monthly distribution of acute MI incidence using data from the community surveillance component of the Atherosclerosis Risk in Communities (ARIC) Study. Methods: We estimated monthly rates of incident hospitalized acute MI from community-wide surveillance of 35 to 84 year old residents of the 4 ARIC Study communities (415,000 base population) from 2006 to 2010. Diagnostic classifications of all hospitalized MI events were independently validated using standardized algorithms applied to data on chest pain history, electrocardiographic evidence and cardiac biomarkers obtained from medical record abstraction. Age adjusted event rates (95% confidence intervals) per 10,000 persons stratified by ARIC community were calculated using population denominators estimated from United States census data. Analyses were weighted to account for the underlying sampling scheme. Results: From 2006 - 2010, a total of 8,578 estimated hospitalized MI events occurred, on the basis of 3,692 hospitalizations sampled. Of these, 71% [6,090 of 8,578] were in persons with no recorded history of MI. Overall, rates of incident MI varied across the months. Distributions of incident MI by month differed between ARIC communities, ranging from a monthly rate of 13.5/10,000 to 45.1/10,000 persons. In Forsyth, NC, we observed the highest monthly rates of incident MI in June [41.1 (23.0, 59.2)] and July [37.3 (26.5, 48.2)], and the lowest rates in September [26.2 (19.0, 33.5)] and March [27.8 (19.1, 36.4)]. Within Jackson, MS, event rates ranged from minimums of 27.1 (18.2, 35.9) and 28.2 (15.4, 40.9) in January and June to maximums of 45.1 (30.4, 59.8) and 39.9 (27.2, 52.7) in May and August. In Minneapolis, MN, the highest monthly rates of incident MI occurred in June [30.0 (19.8, 40.2)] and December [25.3 (12.6, 38.0)], and the lowest rates in October [13.5 (8.4, 18.6)] and September [15.5 (10.5, 20.5)]. Within Washington County, MD, rates of incident MI peaked in April [29.2 (18.3, 40.1)] and November [27.2 (15.8, 38.6)], and reached lows in August [14.7 (9.9, 19.4)] and January [17.0 (11.3, 22.8)]. Conclusions: From 2006 - 2010, monthly distributions of incident MI rates differed between ARIC communities. Across the climatologically diverse ARIC sites, we did not observe seasonal patterns of MI incidence typically reported of CHD mortality (i.e. winter peaks and summer troughs). Triggers for incident MI events are complex and these data suggest they may involve factors not predominately tied to seasonal transitions in these communities. more...
- Published
- 2014
- Full Text
- View/download PDF
36. Nervous system autoantibodies and vitamin D receptor gene polymorphisms in hemodialysis patients
- Author
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Darius L, Mason, Magdalene M, Assimon, Jeffrey R, Bishop, and Hassan A N, El-Fawal
- Subjects
Male ,Polymorphism, Genetic ,Genotype ,Nerve Tissue Proteins ,Middle Aged ,Nervous System ,Polymorphism, Single Nucleotide ,Article ,Renal Dialysis ,Humans ,Receptors, Calcitriol ,Female ,Biomarkers ,Autoantibodies - Abstract
Cognitive deficits are prevalent in hemodialysis (HD) patients. Vitamin D deficiency and vitamin D receptor (VDR) gene single nucleotide polymorphism (SNPs) have been linked to both neurodegeneration (ND) and neuroprotection, respectively. Autoantibodies (Ab) to myelin basic protein (MBP), glial fibrillary acidic protein (GFAP), and neurofilament (NF) triplet proteins arise secondary to nervous system (NS) damage providing a means to assess neurological injury. Characterization of Ab biomarkers of NS damage in HD patients, their association with VDR SNPs, and nutritional vitamin D (NVD) therapy was performed. VDR genotypes, cytokines, and Ab biomarkers to NS proteins in HD subjects receiving ergocalciferol (n = 40) were compared with nonusers (n = 71). Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and immunoglobulin G (IgG) titers against NFs, GFAP, and MBP were measured by immunoassay. Subjects were genotyped for VDR SNPs BsmI (rs1544410) and FokI (rs2228570). Subjects (age 63.3 ± 16.1 years, 66% male) who were C allele carriers of BsmI had higher values of NF-68 antibody titers (p = 0.027). Ergocalciferol users (n = 40) compared with nonusers (n = 71) had lower Ab titers to NS proteins; however, only anti-NF-160 and anti-MBP titers were significantly (p0.05) higher. IgG against NS proteins in HD patients suggests neuronal and glial insult and a relationship with VDR alleles. NVD may provide some neuroprotection, indicated by anti-NF-160 and anti-MBP, which was markedly lowered in ergocalciferol patients. This preliminary study suggests that Ab detection may be useful in monitoring ND and the potential of NVD for neuroprotection in HD patients. more...
- Published
- 2012
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