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Real-world data (RWD) from electronic health records (EHRs) and administrative claims databases are used increasingly to generate real-world evidence (RWE). RWE is used to support clinical evidence packages for medicines that inform decision-makers. In this review of current issues in the use of RWD-derived external comparator groups to support regulatory filings, we assess a series of topics that generally apply across many disease indications. However, most of the examples and illustrations focus on the oncology clinical research setting. The topics include an overview of current uses of RWD in drug development, a discussion of regulatory filings using RWD-derived external comparators, a brief overview of guidance documents and white papers pertaining to external comparators, a summary of some limitations and methodological issues in the use of external comparator groups and finally, a look at the future of this area and recommendations.

Guidelines recommend primary prophylactic (PP) granulocyte colony stimulating factor (G-CSF) for prevention of febrile neutropenia (FN) in patients receiving myelosuppressive chemotherapy with high risk (HR: 20%), or intermediate risk (IR:10-20%) of FN and ≥ 1 patient risk factor (e.g., age ≥ 65y). The current retrospective cohort study describes patterns of PP-G-CSF in older Medicare patients undergoing myelosuppressive chemotherapy with HR/IR of FN.Patients aged ≥ 66y initiating chemotherapy regimens with HR/IR of FN to treat breast, colorectal, lung, or ovarian cancer, or Non-Hodgkin's Lymphoma were selected using Medicare 20% sample (2013-2015) and 100% cancer patient (2014-2017) data. PP-G-CSF use was identified in the first cycle. Timing of pegfilgrastim pre-filled syringe (PFS) administration, proportion of patients completing all cycles (adherence) with pegfilgrastim PFS or on-body injector (OBI), and duration of short-acting G-CSF (sG-CSF) was described across all cycles.Of 64,893 patients receiving HR/IR for FN, 71% received HR and 29% IR regimens. Overall, PP-G-CSF use in the first cycle was 53% (HR: 74%; IR: 44%) and varied across cancers. Adherence with pegfilgrastim was slightly higher among OBI initiators (78%) than PFS (74%). Number of PP-sG-CSF administrations (mean [SD]) per cycle was 5.1 (SD: 2.7) overall, 5.4 (2.6) for HR, and 4.9 (2.7) for IR.Despite cancer treatment guidelines recommending PP-G-CSF use to reduce risk of FN associated with HR and IR (with ≥ 1 patient risk-factor) regimens, PP-G-CSF remains underutilized in older patients, across cancer types and regimens. Opportunities exist for improvement in use of PP-G-CSF.

In this international study, we examined the incidence of hip fractures, postfracture treatment, and all-cause mortality following hip fractures, based on demographics, geography, and calendar year. We used patient-level healthcare data from 19 countries and regions to identify patients aged 50 years and older hospitalized with a hip fracture from 2005 to 2018. The age- and sex-standardized incidence rates of hip fractures, post-hip fracture treatment (defined as the proportion of patients receiving anti-osteoporosis medication with various mechanisms of action [bisphosphonates, denosumab, raloxifene, strontium ranelate, or teriparatide] following a hip fracture), and the all-cause mortality rates after hip fractures were estimated using a standardized protocol and common data model. The number of hip fractures in 2050 was projected based on trends in the incidence and estimated future population demographics. In total, 4,115,046 hip fractures were identified from 20 databases. The reported age- and sex-standardized incidence rates of hip fractures ranged from 95.1 (95% confidence interval [CI] 94.8–95.4) in Brazil to 315.9 (95% CI 314.0–317.7) in Denmark per 100,000 population. Incidence rates decreased over the study period in most countries; however, the estimated total annual number of hip fractures nearly doubled from 2018 to 2050. Within 1 year following a hip fracture, post-hip fracture treatment ranged from 11.5% (95% CI 11.1% to 11.9%) in Germany to 50.3% (95% CI 50.0% to 50.7%) in the United Kingdom, and all-cause mortality rates ranged from 14.4% (95% CI 14.0% to 14.8%) in Singapore to 28.3% (95% CI 28.0% to 28.6%) in the United Kingdom. Males had lower use of anti-osteoporosis medication than females, higher rates of all-cause mortality, and a larger increase in the projected number of hip fractures by 2050. Substantial variations exist in the global epidemiology of hip fractures and postfracture outcomes. Our findings inform possible actions to reduce the projected public health burden of osteoporotic fractures among the aging population.

Purpose Secondary hyperparathyroidism (SHPT) is common among dialysis patients, and calcimimetics are a mainstay of treatment. This study assessed whether cinacalcet use is associated with gastrointestinal bleeding in a large hemodialysis cohort. Methods A linked database of clinical records and medical claims for patients receiving hemodialysis in a large dialysis organization, 2007-2010, was used. A nested case-control study was performed among patients aged ≥18 years who had received hemodialysis for ≥90 days, had Medicare Parts A, B, and D coverage for ≥1 year, and had clinical evidence of SHPT (parathyroid hormone >300 pg/mL). Cases were those who experienced death or hospitalization caused by gastrointestinal bleeding. Each case was matched to up to four controls. Exposure was measured by any cinacalcet use, current use, past use, cumulative exposure days, and cumulative dosage. Conditional logistic models were used to assess the association. Results Of 48 437 patients included, 2570 experienced gastrointestinal bleeding events (2498 non-fatal, 72 fatal), and 2465 (2397 non-fatal, 68 fatal) were matched to 9500 controls; 17.2% of cases and 15.8% of controls had cinacalcet exposure and 11.1% of both cases and controls had current use. The adjusted odds ratios (95% CI) of gastrointestinal bleeding for any use, current use, and past use of cinacalcet were 1.04 (0.91-1.19), 0.97 (0.83-1.13), and 1.22 (0.99-1.50), respectively, with no use as the reference. Conclusion The results do not suggest an elevated risk of gastrointestinal bleeding resulting in hospitalization or death for hemodialysis patients exposed to cinacalcet.

Evaluate the relationship between duration of primary prophylactic short-acting granulocyte colony-stimulating factor (PP-sG-CSF) and risk of neutropenia-related hospitalization (NRH) in older patients receiving myelosuppressive chemotherapy.Using the Medicare claims database, we conducted a nested case-control study in a cohort of patients aged ≥66 years with breast, colorectal, lung, ovarian, or prostate cancer, or non-Hodgkin lymphoma who initiated a first cycle of any myelosuppressive chemotherapy January 1, 2008-September 30, 2016, and received PP-sG-CSF. We matched up to four controls to each NRH case by age, cancer type, regimen febrile neutropenia (FN) risk category, and year using incidence density sampling. We used conditional logistic regression adjusted for race, sex, and modified Charlson comorbidity index (CCI) to estimate relative risk of NRH related to duration of PP-sG-CSF categorized as5 and ≥ 5 days.Of 2148 patients receiving PP-sG-CSF, 108 (5%) experienced NRH in the first cycle. We matched 333 controls to 96 cases. Cases were similar to controls in mean age, tumor type, and intermediate/high-risk regimen, but were more likely to have CCI ≥5 and less likely to use PP-sG-CSF ≥5 days (31% vs. 39%). Adjusted ORs (95% CI) for NRH were 0.69 (0.40-1.19) for ≥5 vs.5 days of PP-sG-CSF among patients receiving any myelosuppressive chemotherapy, 0.43 (0.21-0.89) for intermediate/high-risk regimen, and 0.42 (0.19-0.89) for any myelosuppressive chemotherapy with all agents given on cycle day one only.Among older patients with cancer who are receiving PP-sG-CSF, ≥5 days of use was associated with substantial reduction in NRH risk.

Purpose To evaluate patterns of primary prophylactic (PP) granulocyte colony–stimulating factor (G-CSF) use following chemotherapy by cancer type and febrile neutropenia (FN) risk. Methods Using a commercial administrative database, we identified adult patients diagnosed with breast, colorectal, lung, ovarian cancer, or non-Hodgkin lymphoma (NHL) who initiated chemotherapy with high risk (HR) or intermediate risk (IR) for FN between January 1, 2013, and August 31, 2017. We describe use of PP-G-CSF, proportion completing all their cycles with pegfilgrastim, timing of pegfilgrastim, and duration of short-acting G-CSF. Results Among 22,868 patients (breast 11,513; colorectal 3765; lung 4273; ovarian 1287; and NHL 2030), 36.8% received HR and 63.2% received IR (64.4% of whom had ≥ 1 risk factor [RF] for FN). Proportions of patients receiving PP-G-CSF in the first cycle were 76.1%, 28.2%, and 26.4% among patients receiving HR, IR, and IR plus ≥ 1 RF, respectively. Among breast cancer patients receiving HR regimens and initiating PP-pegfilgrastim, 60.4% (95% confidence interval [CI] 57.2–63.6%) initiating via on-body injector (OBI) and 51.9% (95% CI 48.0–55.8%) initiating via prefilled syringe (PFS) completed all their cycles with OBI and PFS, respectively. Among all cycles with PP-PFS, 8.5% received PFS on the same day as chemotherapy completion. Mean administrations/cycle were 3.2 (standard deviation [SD] 2.3) for filgrastim, 3.0 (SD 1.6) for filgrastim-sndz, and 4.3 (SD 2.5) for tbo-filgrastim. Conclusions There is under- and mistimed use of PP-G-CSF among patients at HR for FN. Novel pegfilgrastim delivery devices could help breast cancer patients at HR for FN complete all their cycles with timely prophylaxis.

BackgroundPrior studies have developed a chronic kidney disease–mineral and bone disorder (CKD-MBD) composite score based on combinations of calcium (Ca), phosphorus (P) and parathyroid hormone (PTH) that have been shown to be associated with an increased risk of clinical outcomes in the USA. We examined this association in a contemporary, international cohort of hemodialysis patients.MethodsWe studied 19 313 patients surviving ≥12 months in the Dialysis Outcomes and Practice Patterns Study Phases 3–5 (2005–15) from Europe, Canada and the USA. The CKD-MBD composite score was defined as the number of markers above target levels (P, 3.5–5.5 mg/dL; Ca, 8.4–10.2 mg/dL; PTH, 150–600 pg/mL). Using Cox models, we estimated hazard ratios (HRs) for death and a composite event (death or hospitalization), contrasting MBD 2/3 (2–3 parameters above target) with MBD 0 (all in target), adjusted for a disease risk score (DRS).ResultsMBD 2/3 above target was observed in 10–14% of patients across regions and was associated with greater DRS-adjusted mortality {HR 1.41 [95% confidence interval (CI) 1.10–1.82]} and composite events [HR 1.23 (95% CI 1.10–1.38)] in the USA compared with MBD 0; the mortality association was stronger for patients ≥ 65 years of age [HR 1.82 (95% CI 1.28–2.58)] compared with patients ConclusionsSimultaneous consideration of Ca, P and PTH may help in identifying patients on dialysis with a higher risk of major clinical outcomes related to CKD-MBD.

Purpose As more biosimilars become available in the United States, postapproval noninterventional studies describing biosimilar switching and comparing effectiveness and/or safety between switchers and nonswitchers will play a key role in generating real-world evidence to inform clinical practices and policy decisions. Ensuring sound methodology is critical for making valid inferences from these studies. Methods The Biologics and Biosimilars Collective Intelligence Consortium (BBCIC) convened a workgroup consisting of academic researchers, industry scientists, and practicing clinicians to establish best practice recommendations for the conduct of noninterventional studies of biosimilar and reference biologic switching. The workgroup members participated in eight teleconferences between August 2017 and February 2018 to discuss specific topics and build consensus. Results This report provides workgroup recommendations covering five main considerations relating to noninterventional studies describing reference biologic to biosimilar switching and comparing reference biologic to biosimilars for safety and effectiveness in the presence of switching at treatment initiation and during follow-up: (a) selecting appropriate data sources from a range of available options including insurance claims, electronic health records, and registries; (b) study designs; (c) outcomes of interest including health care utilization and clinical endpoints; (d) analytic approaches including propensity scores, disease risk scores, and instrumental variables; and (e) special considerations including avoiding designs that ignore history of biologic use, avoiding immortal time bias, exposure misclassification, and accounting for postindex switching. Conclusion Recommendations provided in this report provide a framework that may be helpful in designing and critically evaluating postapproval noninterventional studies involving reference biologic to biosimilar switching.

On June 23, 2020, Prolia® (denosumab) was approved by the National Medical Products Administration (NMPA) in the People’s Republic of China as the first monoclonal antibody for the treatment of postmenopausal women with osteoporosis at high risk of fractures. Its brand name in Chinese is 普罗力, a transliteration from the English name “Prolia”, which has an implied meaning of “to give strength to everyone”— a suitable name for a potent anti-resorptive therapy. The approval was supported by a novel marketing authorization application (MAA) that included data from Prolia’s global clinical trial program establishing favorable efficacy and safety, augmented by results from a real-world evidence (RWE) study confirming the effectiveness and safety of Prolia in clinical practice within Taiwan and Hong Kong. Key constructs for this registration-quality RWE study included the fit-for-purpose assessment of data quality, methodology and quantitative assessment of potential biases, good practices of study conduct, and reproducibility of results. Using data from clinical practice in Taiwan and Hong Kong to evaluate the benefits versus risks of Prolia treatment in ethnic Chinese women with postmenopausal osteoporosis, the RWE study results for effectiveness were comparable to efficacy demonstrated in the global clinical trial program and results for safety were consistent with the incidence observed in global post-marketing safety studies. While RWE is often used to monitor postmarket safety of drug products, support health insurance coverage decisions, and inform clinicians on real-world use of medicines, it has not been widely used to support regulatory approval for new medicines in lieu of clinical bridging studies in countries where such studies are required. Well-conducted registrational RWE studies can play a pivotal role in complementing the totality of evidence presented in an MAA. The benefits of such an approach include avoiding the collection of additional placebo-controlled trial data in populations where adequate ethnic characterization of efficacy, effectiveness, and safety may already exist from postmarketing sources, and accelerate access for patients to innovative medicines in important regions. Here, we describe a regulatory case study of a novel MAA incorporating RWE that provided important evidence to confirm the benefit:risk of a new drug and facilitated a label expansion to a new patient population.

Purpose: In contrast to randomized clinical trials, comparative safety and effectiveness assessments of osteoporosis medications in clinical practice may be subject to confounding by indication. We used negative control outcomes to detect residual confounding when comparing osteoporosis medications. Methods: Using MarketScan Commercial and Supplemental claims, we identified women aged ≥55 years who initiated an oral bisphosphonate (BP) (risedronate, alendronate, or ibandronate), denosumab (an injected biologic), or intravenous zoledronic acid (ZA) from October 1, 2010 to September 30, 2015. Women with Paget's disease or cancer were excluded. We compared individual oral BPs to each other, denosumab to ZA, denosumab to oral BPs, and ZA to oral BPs, with respect to 11 negative control outcomes identified by subject matter experts. We estimated the 12-month cumulative risk difference (RD) using inverse probability of treatment and censoring weights. Results: Among 148 587 women, most initiated alendronate (57%), followed by ibandronate (12%), ZA (11%), risedronate (10%), and denosumab (10%). Compared with denosumab, patients initiating ZA had similar risks of all negative control outcomes. Compared with oral BPs, patients initiating denosumab had a higher risk of a wellness visit (RD = 1.2%, 95% CI: 0.4, 1.9) and a lower risk of receiving herpes zoster vaccine (RD = −0.6%, 95% CI: −1.1, −0.2). Comparing ZA with oral BP initiators resulted in two outcomes with positive associations. Conclusions: Caution is warranted when comparing injectable vs oral osteoporosis medications, given the potential for unmeasured confounding. Evaluating negative control outcomes could be a standard validity check prior to conducting comparative studies.

Introduction Red blood cell transfusions have been associated with infection risk. We investigated whether hospital transfusions are associated with infections in maintenance hemodialysis patients requiring transfusions for chronic anemia. Methods In this retrospective cohort study, hemodialysis patients who experienced an incident hospitalization during 2012-2013 were identified from the Medicare end-stage renal disease database. Hospital transfusions were first categorized into one of five groups based on adjusted likelihood of administering red blood cell transfusions during inpatient hospital stays that occurred over the previous year (2011) among the general Medicare cohort. Next, in a patient-level analysis, patients were categorized according to transfusion use at the incident hospitalization hospital. Outcomes were infection-related rehospitalization and a composite of infection-related hospitalization and all-cause mortality during the 60 days following hospital discharge. We estimated adjusted rate ratios for the association between hospital transfusion use and risk of rehospitalization or the composite endpoint using Poisson regression models. Findings The study included 1578 hospitals and 61,455 hemodialysis patients. Patient characteristics were balanced across hospital transfusion use groups. The overall transfusion rate was 16.0%. The overall 30-day infection-related hospitalization rate (95% confidence interval) per 100 patient-months was 8.8 (8.6-9.1); rates did not differ by transfusion use group. Rate ratios for infection-related rehospitalization were 1.00 (0.91-1.10) over 30 days and 0.98 (0.91-1.05) over 60 days comparing the lowest and highest transfusion use groups. Discussion We found no differences in risk of infection-related rehospitalization for patients receiving maintenance hemodialysis across the varying blood transfusion rates of US hospitals.

Purpose Missed in-center hemodialysis treatments (MHT) are a general indicator of health status in hemodialysis patients. This analysis was conducted to estimate the association between cinacalcet use and MHT rate. Methods We studied patients receiving hemodialysis and prescription benefits services from a large dialysis organization. Incident cinacalcet users were propensity score matched to controls on 31 demographic, clinical, and laboratory variables. We applied inverse probability (IP) of censoring and crossover weights to account for informative censoring. Weighted negative binomial modeling was used to estimate MHT rates and pooled logistics models were used to estimate the association between cinacalcet use and MHT. Results Baseline demographic and clinical variables included serum calcium, phosphorus, parathyroid hormone, and vitamin D use, and were balanced between 15,474 new cinacalcet users and 15,474 matched controls. In an analysis based on intention-to-treat principles, 40.8% of cinacalcet users and 46.5% of nonusers were censored. MHT rate was 13% lower among cinacalcet initiators versus controls: IP of censoring weighted incidence rate ratio was 0.87 (95% confidence interval [CI]: 0.84–0.90 p

Erythropoiesis-stimulating agents (ESAs) are commonly used to treat anemia in patients with CKD, including those receiving dialysis, although clinical trials have identified risks associated with ESA use. We evaluated the effects of changes in dialysis payment policies and product labeling instituted in 2011 on mortality and major cardiovascular events across the United States dialysis population in an open cohort study of patients on dialysis from January 1, 2005, through December 31, 2012, with Medicare as primary payer. We compared observed rates of death and major cardiovascular events in 2011 and 2012 with expected rates calculated on the basis of rates in 2005-2010, accounting for differences in patient characteristics and influenza virulence. An abrupt decline in erythropoietin dosing and hemoglobin concentration began in late 2010. Observed rates of all-cause mortality, cardiovascular mortality, and myocardial infarction in 2011 and 2012 were consistent with expected rates. During 2012, observed rates of stroke, venous thromboembolic disease (VTE), and heart failure were lower than expected (absolute deviation from trend per 100 patient-years [95% confidence interval]: -0.24 [-0.08 to -0.37] for stroke, -2.43 [-1.35 to -3.70] for VTE, and -0.77 [-0.28 to -1.27] for heart failure), although non-ESA-related changes in practice and Medicare payment penalties for rehospitalization may have confounded the results. This initial evidence suggests that action taken to mitigate risks associated with ESA use and changes in payment policy did not result in a relative increase in death or major cardiovascular events and may reflect improvements in stroke, VTE, and heart failure.

Purpose Confounding, a concern in nonexperimental research using administrative claims, is nearly ubiquitous in claims-based pharmacoepidemiology studies. A fixed-length look-back window for assessing comorbidity from claims is common, but it may be advantageous to use all historical claims. We assessed how the strength of association between a baseline-identified condition and subsequent mortality varied by when the condition was measured and investigated methods to control for confounding. Methods For Medicare beneficiaries undergoing maintenance hemodialysis on 1 January 2008 (n = 222 343), we searched all Medicare claims, 1 January 2001 to 31 December 2007, for four conditions representing chronic and acute diseases, and classified claims by number of months preceding the index date. We used proportional hazard models to estimate the association between time of condition and subsequent mortality. We simulated a confounded comorbidity–exposure relationship and investigated an alternative method of adjustment when the association between the condition and mortality varied by proximity to follow-up start. Results The magnitude of the mortality hazard ratio estimates for each condition investigated decreased toward unity as time increased between index date and most recent manifestation of the condition. Simulation showed more biased estimates of exposure–outcome associations if proximity to follow-up start was not considered. Conclusions Using all-available claims information during a baseline period, we found that for all conditions investigated, the association between a comorbid condition and subsequent mortality varied considerably depending on when the condition was measured. Improved confounding control may be achieved by considering the timing of claims relative to follow-up start. Copyright © 2015 John Wiley & Sons, Ltd.

Background Little is known about changes in parathyroid hormone (PTH), calcium and phosphorous levels after parathyroidectomy in hemodialysis patients. We studied the effects of parathyroidectomy on these biochemical values in a large cohort of patients receiving maintenance hemodialysis. Methods This retrospective cohort study included patients identified in both the United States Renal Data System and the database of a large dialysis organization who underwent parathyroidectomy in 2007-09, were aged ≥ 18 years, had Medicare Parts A and B as primary payer and had received hemodialysis for ≥ 1 year pre-parathyroidectomy. Descriptive statistics were calculated for continuous variables; categorical variables were used to characterize the population and evaluate monthly laboratory and medication use; median values were calculated for laboratory measures. Results Among 1402 parathyroidectomy patients, mean age was 48.9 years, 52.4% were males, 58.8% were African American and mean dialysis duration was 7.5 years. Median PTH levels increased over the year before parathyroidectomy from 1039 to 1661 pg/mL and decreased afterward to 98 pg/mL at 1 month; levels remained ≥ 897 pg/mL for 10% of patients. Median calcium levels fell from 9.6 mg/dL before to 7.9 mg/dL 1 month after parathyroidectomy; levels were ≤ 7.1 mg/dL for 25% and remained ≤ 7.2 mg/dL for the lowest 25% at 3 months. Median phosphorous level was 6.8 mg/dL immediately before parathyroidectomy, decreased to 3.8 mg/dL immediately after and reached 5.8 mg/dL at 1 year. Conclusions While PTH levels dropped after parathyroidectomy for most patients, surgery was sometimes ineffective in reducing levels and sometimes led to over-suppression. Hypocalcemia could be profound and long lasting, suggesting the need for prolonged vigilance.

Purpose Cinacalcet is indicated for treatment of secondary hyperparathyroidism in patients receiving hemodialysis. Cinacalcet reduces serum calcium concentrations by decreasing parathyroid hormone secretion, but the frequency and degree of calcium reduction following cinacalcet initiation, subsequent physician response, and ultimate calcium recovery in clinical practice are not well described. Methods Patients receiving hemodialysis at a large dialysis organization who enrolled in the organization's prescription benefits service and initiated cinacalcet at serum calcium ≥8.4 mg/dL were studied (N = 13 723). Patients were categorized by whether they experienced a reduction in calcium to

Purpose In recent years, the use of red blood cell (RBC) transfusion for the treatment of chronic kidney disease (CKD)-related anemia has increased. We used the OptumInsight medical claims database to study the association between receiving a transfusion and hyperkalemia and heart failure events. Methods Persons 18–64 years of age with diagnosed stage 4 or 5 CKD (not requiring dialysis) between 2006 and 2010 were followed until their first hospitalization or emergency room visit with a diagnosis of hyperkalemia or heart failure, termination of insurance coverage, or death. We used a case-only design and conditional logistic regression to estimate rate ratios (RR) and 95% confidence intervals (CIs) describing associations between RBC transfusion and the risks of hyperkalemia or heart failure. We used single (1:1) and variable (1:m) self-control matching intervals, with adjustment for time-varying confounders. Results Seven thousand eight hundred twenty-nine individuals met our inclusion criteria; two-thirds were age 50 years or older; 43% were women and 51% had diabetes. Rates of hyperkalemia and heart failure were 7.9/100 person-years (95%CI: 7.3, 8.5) and 16.3/100 person-years (95%CI: 15.5, 17.2), respectively. RBC transfusion was associated with an increased risk of both hyperkalemia (single interval matched RR = 12.0, 95%CI: 1.3, 109; multiple interval matched RR = 6.1, 95%CI: 2.5, 15.1) and heart failure (single interval matched RR = 1.7, 95%CI: 0.3, 9.2; multiple interval matched RR = 3.8, 95%CI: 1.4, 10.3). Conclusion In patients with advanced CKD, RBC transfusion appears to be associated with an elevated risk of hyperkalemia and heart failure; further investigation into these risks is warranted. Copyright © 2015 John Wiley & Sons, Ltd.

This chapter reviews important aspects of pharmacovigilance of biosimilars. Biologics are structurally complex molecules that are more difficult to characterize, produce, and reproduce than most small-molecule compounds. Ongoing robust pharmacovigilance is critical in the monitoring, detection, and assessment of safety signals over the life cycle of every biologic. The availability of multisource biologics, including biosimilars, warrants rigorous pharmacovigilance to accurately detect and disaggregate safety signals. Although biosimilars are highly similar to their reference biologics, they are not required or expected to be identical, and regulatory pathways permit slight variations in structural and pharmaceutical attributes and clinical development approaches. During development, candidate biosimilars are evaluated in a stepwise manner against their reference product for similarity in structure, function, clinical efficacy, and safety. However, clinical studies to evaluate biosimilarity may not detect rare adverse events, and potential differences in safety resulting from minor differences in manufacturing procedures between a biosimilar and its reference product (or other biosimilars) may not be detected before approval. Risk management plans, particularly during the early postmarketing period, are also an important component of pharmacovigilance planning for biosimilars. Important components of pharmacovigilance programs include ongoing and rigorous data collection, adverse event reporting, and analysis of causal relationships resulting in accurate attribution of an adverse event to the correct product. Methods to improve product-specific monitoring, like the assignment of distinguishable nonproprietary names for all biologics and the use of additional product identifiers (e.g., batch number, trade name, manufacturer) for adverse event reporting, are vital to ensure accurate surveillance and traceability of all biologics, including biosimilars.

Background It is important to identify an easily defined subset of patients at increased risk of adverse clinical outcomes associated with mineral and bone disorder (MBD) biomarkers (parathyroid hormone, calcium and phosphate). Methods Observational cohort study of 26 221 prevalent hemodialysis patients in Davita clinics as of 31 August 2005 and followed up until 31 December 2006 (16 months). Predictors were 12 possible definitions of 'clinically important' MBD based on all 3 biomarkers, and 18 alternative definitions based on only 1 or 2 biomarkers. Events were death alone and a composite of cardiovascular hospitalization or death. Excess events were calculated based on a multivariate Cox model using 5224 patients in target for all MBD biomarkers and applied to 20 997 patients out of target for at least one biomarker. Excess events attributable to MBD were estimated by subtracting the multivariate model-derived predicted number from the actual number. Outcomes were the proportion of excess events attributable to MBD captured by each definition (threshold ≥70%) and the reduction in the population size considered to have clinically important MBD (threshold ≥30%). The excess fraction was excess events divided by actual events. Results Patients with more biochemical markers out of target tended to be younger, black and have longer times since starting dialysis. The excess fraction associated with MBD ranged from ∼10 to 26% depending on the clinical endpoint and definition. The only definition to meet the thresholds required at least two of the three MBD biomarkers to be out of target (high or low). It captured 82% of excess composite endpoints and 74% of excess deaths and reduced the at-risk population by 46%. Conclusions Patients with at least two of three MBD biomarkers out of target represent a subgroup of patients at elevated risk of adverse clinical events.

Background and objectives Patients receiving dialysis undergo parathyroidectomy to improve laboratory parameters in resistant hyperparathyroidism with the assumption that clinical outcomes will also improve. However, no randomized clinical trial data demonstrate the benefits of parathyroidectomy. This study aimed to evaluate clinical outcomes up to 1 year after parathyroidectomy in a nationwide sample of patients receiving hemodialysis. Design, setting, participants, & measurements Using data from the US Renal Data System, this study identified prevalent hemodialysis patients aged ≥18 years with Medicare as primary payers who underwent parathyroidectomy from 2007 to 2009. Baseline characteristics and comorbid conditions were assessed in the year preceding parathyroidectomy; clinical events were identified in the year preceding and the year after parathyroidectomy. After parathyroidectomy, patients were censored at death, loss of Medicare coverage, kidney transplant, change in dialysis modality, or 365 days. This study estimated cause-specific event rates for both periods and rate ratios comparing event rates in the postparathyroidectomy versus preparathyroidectomy periods. Results Of 4435 patients who underwent parathyroidectomy, 2.0% died during the parathyroidectomy hospitalization and the 30 days after discharge. During the 30 days after discharge, 23.8% of patients were rehospitalized; 29.3% of these patients required intensive care. In the year after parathyroidectomy, hospitalizations were higher by 39%, hospital days by 58%, intensive care unit admissions by 69%, and emergency room/observation visits requiring hypocalcemia treatment by 20-fold compared with the preceding year. Cause-specific hospitalizations were higher for acute myocardial infarction (rate ratio, 1.98; 95% confidence interval, 1.60 to 2.46) and dysrhythmia (rate ratio 1.4; 95% confidence interval1.16 to 1.78); fracture rates did not differ (rate ratio 0.82; 95% confidence interval 0.6 to 1.1). Conclusions Parathyroidectomy is associated with significant morbidity in the 30 days after hospital discharge and in the year after the procedure. Awareness of clinical events will assist in developing evidence-based risk/benefit determinations for the indication for parathyroidectomy.

Changes in anemia management practices due to concerns about erythropoiesis-stimulating agent safety and Medicare payment changes may increase patient risk of transfusion. We examined anemia management trends in hemodialysis patients and risk of red blood cell (RBC) transfusion according to dialysis facility-level hemoglobin concentration.Retrospective follow-up study; 6-month study period (January to June), 3-month exposure/follow-up.For each year in 2007-2011, annual cohorts of point-prevalent Medicare primary payer patients receiving hemodialysis on January 1 with one or more hemoglobin measurements during the study period. Annual cohorts averaged 170,000 patients, with 130,000 patients and 3,100 facilities for the risk analysis.Percentage of facility patient-months with hemoglobin level10 g/dL.Patient-level RBC transfusion rates.Monthly epoetin alfa and intravenous iron doses, mean hemoglobin levels, and RBC transfusion rates; percentage of facility patient-months with hemoglobin levels10 g/dL (exposure) and patient-level RBC transfusion rates (follow-up).Percentages of patients with hemoglobin levels10 g/dL increased every year from 2007 (6%) to 2011 (~11%). Epoetin alfa doses, iron doses, and transfusion rates remained relatively stable through 2010 and changed in 2011. Median monthly epoetin alfa and iron doses decreased 25% and 43.8%, respectively, and monthly transfusion rates increased from 2.8% to 3.2% in 2011, a 14.3% increase. Patients in facilities with the highest prevalence of hemoglobin levels10 g/dL over 3 months were at ~30% elevated risk of receiving RBC transfusions within the next 3 months (relative risk, 1.28; 95% CI, 1.22-1.34).Possibly incomplete claims data; smaller units excluded; hemoglobin levels reported monthly for patients receiving epoetin alfa; transfusions usually not administered in dialysis units.Dialysis facility treatment practices, as assessed by percentage of patient-months with hemoglobin levels10 g/dL over 3 months, were associated significantly with risk of transfusions in the next 3 months for all patients in the facility, regardless of patient case-mix.

e18181 Background: In clinical trials, efficacy of 10–11 days of primary prophylactic (PP) sG-CSF is similar to a single dose of pegfilgrastim for preventing febrile neutropenia (FN). However, most patients receive < 10 days of PP sG-CSF in clinical practice. This study assessed the effect of PP sG-CSF duration on the risk of NRH. Methods: Using Medicare 20% sample data, we conducted a nested case-control study within a cohort of patients aged ≥66 y with breast, colorectal, lung, ovarian, or prostate cancer or NHL who initiated first cycle of chemotherapy 1/1/2008–9/30/2016, had ≥1 y continuous coverage in Medicare parts A and B before cycle day 1 (baseline), and received PP sG-CSF. We identified NRH cases (ICD-9, 288.0X; ICD-10, D70.X) from cycle day 5 to end of cycle 1. We matched each case to up to 4 controls based on age (± 1 y), tumor type, regimen risk for FN (intermediate/high [ > 10%], other), and year using incidence density sampling. Duration of sG-CSF (days of use from cycle day 1 to the day before case date) was categorized as < 5 and ≥5 days. We used conditional logistic regression adjusted for race, sex, and Charlson comorbidity index (CCI) at baseline to estimate relative risk of NRH related to duration of sG-CSF. Results: Of 1431 patients receiving PP sG-CSF, 68 cases matched 231 controls. Cases were similar to controls in age (76 vs 75 y), tumor type (NHL, 62% vs 62%; lung cancer, 25% vs 25%), intermediate-/high-risk regimen (65% vs 67%), and male sex (50% vs 48%) but had slightly higher CCI (3.9 vs 3.3). The percentage of patients with ≥5 days of PP sG-CSF use was 26% in cases and 41% in controls. The adjusted OR (95% CI) for NRH was 0.48 (0.25–0.93) for ≥5 vs < 5 days of PP sG-CSF; results were consistent across sensitivity analyses (Table). Conclusions: Among elderly cancer patients receiving PP sG-CSF, ≥5 days of sG-CSF use was associated with substantial reduction in the risk of NRH.[Table: see text]

Background/Aims: Predialysis care has been associated with improved first-year outcomes. We investigated types of predialysis care associated with improved patient outcomes in patients initiating dialysis with a fistula and at least 2 years of predialysis care. Methods: In this retrospective cohort of incident hemodialysis patients with ≥2 years of Medicare coverage before dialysis initiation, care patterns and patients were determined using Medicare claims. Fistula use at initiation was ascertained from the Medical Evidence Report. Results: Patients aged ≥67 years who initiated hemodialysis with a fistula (n = 14,459) differed demographically and clinically from patients who initiated with other vascular access types; however, 55% had diabetes, 28% heart failure, and 40% ischemic heart disease. In the year preceding initiation, 88% of these patients visited a nephrologist, 66% a cardiologist, 9% an endocrinologist, and 3% a dietician; most underwent routine laboratory measurements. In the first year of dialysis, 50% were hospitalized and 1.3% underwent transplant; the mortality rate remained constant (∼20 per 100 patient-years). Of predialysis care factors evaluated, only fistula placement more than 1 month before dialysis initiation was associated with lower hospitalization and mortality risk and greater likelihood of transplant. Other potentially modifiable factors included more contact with cardiologists and endocrinologists. Conclusion: Patients initiating dialysis with a functioning fistula appear to receive substantial predialysis preparation. This selected population does not show the excess mortality risk often observed early in dialysis treatment. Earlier fistula placement and referral to cardiology and endocrinology appear to be important aspects of predialysis care.

Changes in anemia management over the past decade have produced downward shifts in hemoglobin concentrations. We aimed to examine the effect on use of red blood cell (RBC) transfusions.Retrospective cohort study.We identified point prevalent Medicare hemodialysis patients as of January 1 of each year (1999-2010) and categorized them based on 3-month (April to June) mean hemoglobin levels (10 or ≥10 g/dL) in each year.Hemoglobin patterns over time and clinical profiles based on achieved hemoglobin concentrations.RBC transfusion use.We used negative binomial modeling to examine the effect of hemoglobin level10 g/dL on transfusion use, adjusting for case-mix differences.Proportions of patients with mean hemoglobin levels10 g/dL decreased from 10% (1999) to ~4% (2005), but began increasing after 2006 and reached 6% by 2010. Accounting for case-mix differences, transfusion rates remained relatively constant at approximately 7.9 per 100 person-months for patients with hemoglobin levels10 g/dL and 2 per 100 person-months for patients with hemoglobin levels ≥10 g/dL. Patients with average hemoglobin levels10 g/dL were more likely to receive transfusions (risk ratio, 2.2; 95% CI, 2.1-2.2) even after adjustment; the risk ratio doubled if hemoglobin levels remained10 g/dL for 6 months (4.4; 95% CI, 3.7-5.2).Limited in generalizability to patients with Medicare as primary payer; residual confounding from factors such as frailty and chronic inflammation cannot be excluded; categorizing patients based on an average of 3 outpatient hemoglobin measurements may introduce some misclassification.Risk of transfusion increases substantially with hemoglobin concentrations10 g/dL; risk appears to be independent of other clinical factors. If anemia management patterns shift toward lower hemoglobin concentrations, RBC transfusion use likely will increase in dialysis patients.

Patients with ESRD have a substantially increased risk of bone fractures, but the burden of fractures has not been sufficiently characterized in this population. Here, we analyzed fracture rates and postdischarge outcomes using Medicare data from hemodialysis patients in the United States between 2000 and 2009. We assessed adjusted quarterly fracture rates (inpatient and outpatient) and consequences of postfracture hospitalization for seven categories of fracture location. Pelvis/hip, vertebral, and lower leg fractures were the most prevalent fracture types. Pelvis/hip fractures declined slightly from 29.6 to 20.6 per 1000 patient-years between early 2000 and late 2009, but the incidence rates for all other fracture types remained relatively constant. Median lengths of stay for the primary fracture hospitalization ranged from 5 days (interquartile range [IQR], 3–9 days) for forearm/wrist fractures to 8 days (IQR, 5–12 days) for femur fractures. The proportion of patients discharged from the primary hospitalization to a skilled-nursing facility ranged from 28% (ribs/sternum) to 47% (pelvis/hip). A negative binomial regression model suggested that patients had an adjusted mean of 3.8–5.2 additional hospitalizations during the year after discharge from the index hospitalization, varying by fracture type, comprising a mean of 33–52 inpatient days. Case-mix–adjusted mortality rates after discharge ranged from 0.43 to 0.91 per patient-year and were highest for vertebral, pelvis/hip, and femur fractures. In conclusion, fractures in the dialysis population are common and are associated with a substantially increased risk for death and hospitalization.

Mortality rates for maintenance hemodialysis patients are much higher than the general population and are even greater soon after starting dialysis. Here we analyzed mortality patterns in 86,886 patients in 11 countries focusing on the early dialysis period using data from the Dialysis Outcomes and Practice Patterns Study, a prospective cohort study of in-center hemodialysis. The primary outcome was all-cause mortality, using time-dependent Cox regression, stratified by study phase adjusted for age, sex, race, and diabetes. The main predictor was time since dialysis start as divided into early (up to 120 days), intermediate (121-365 days), and late (over 365 days) periods. Mortality rates (deaths/100 patient-years) were 26.7 (95% confidence intervals 25.6-27.9), 16.9 (16.2-17.6), and 13.7 (13.5-14.0) in the early, intermediate, and late periods, respectively. In each country, mortality was higher in the early compared to the intermediate period, with a range of adjusted mortality ratios from 3.10 (2.22-4.32) in Japan to 1.15 (0.87-1.53) in the United Kingdom. Adjusted mortality rates were similar for intermediate and late periods. The ratio of elevated mortality rates in the early to the intermediate period increased with age. Within each period, mortality was higher in the United States than in most other countries. Thus, internationally, the early hemodialysis period is a high-risk time for all countries studied, with substantial differences in mortality between countries. Efforts to improve outcomes should focus on the transition period and the first few months of dialysis.

There are few data available on low hemoglobin and incident falls in the general U.S. population.Of 30,239 black and white U.S. adults ≥45 years in the population-based REasons for Geographic And Racial Differences in Stroke study, 16,782 had hemoglobin measured at baseline and follow-up data on falls. Hemoglobin was categorized by 1.0 g/dL increments relative to the World Health Organization anemia threshold (13.0 g/dL for men,12.0 g/dL for women). Recurrent falls (≥2 falls in the 6 months after baseline) were assessed during a telephone interview.Recurrent falls occurred in 3.9% of men and 4.8% of women. Compared with those with a hemoglobin level 1 to 2 g/dL above the anemia cut-off, multivariable adjusted odds ratios (95% confidence intervals) for recurrent falls associated with hemoglobin levels ≥3, 2 to3 and 0 to 1 g/dL above the cut-off point, and 0 to1 and ≥1 g/dL below the cut-off point were 0.73 (0.45-1.19), 0.84 (0.57-1.24), 1.29 (0.88-1.90), 1.32 (0.0.80-1.2.18) and 2.12 (1.23-3.63), respectively, among men (linear trend P0.001), and 1.59 (1.10-2.3), 1.24 (0.95-1.62), 1.42(1.11-1.81), 1.28 (0.91-1.80) and 1.76 (1.13-2.74), respectively, among women (linear trend P = 0.45; quadratic trend P = 0.016).Among men, lower hemoglobin levels were associated with an increased risk for recurrent falls. Although our findings suggest an increased risk for recurrent falls at both lower and higher hemoglobin levels among women, these findings should be confirmed in subsequent studies.

Background Patients receiving hemodialysis with values outside of target levels for parathyroid hormone (PTH: 150–600 pg/mL), calcium (Ca: 8.4–10.2 mg/dL), and phosphate (P: 3.5–5.5 mg/dL) are at elevated morbidity and mortality risk. We examined whether patients receiving care in dialysis facilities where greater proportions of patients have at least two values out of target have a higher risk of adverse clinical outcomes. Methods The study cohort consisted of 39,085 prevalent hemodialysis patients in 1298 DaVita dialysis facilities as of September 1, 2009, followed from January 1, 2010, until an outcome, a censoring event, or December 31, 2010. We determined the quintile of the distribution across facilities of the proportion of patients with at least two of three parameters out of, or above, target over a 4-month baseline period. The primary composite outcome was cardiovascular hospitalization or death. Secondary outcomes included death, cardiovascular hospitalization, and parathyroidectomy. Poisson regression models were used to estimate the association of facility quintile with outcomes. Results Facility quintile was associated with a 7 % increased risk of cardiovascular hospitalization or death (quintile 5 versus 1, RR 1.07, 95 % CI 1.01–1.13) using the out-of-target measure of exposure and a 12 % increased risk (RR 1.12, 95 % CI 1.06–1.19) using the above-target measure. No association was seen for death using either measure. Patients in facility quintiles 3–5 (versus 1) were at increased parathyroidectomy risk (RR ranged from 2.05, 95 % CI 1.10–3.82, for quintile 3 to 2.73, 95 % CI 1.50–4.98, for quintile 5). Conclusions Facility level analysis of a large prevalent sample of US patients on hemodialysis demonstrates that patients in facilities with the least control of PTH, Ca, and P had the greatest risk of parathyroidectomy or the combination of cardiovascular hospitalization or death. Electronic supplementary material The online version of this article (doi:10.1186/s12882-016-0382-8) contains supplementary material, which is available to authorized users.

Fractures are a major source of morbidity and mortality in patients receiving dialysis. We sought to determine whether rates of fractures and tendon ruptures vary geographically.Data from the US Renal Data System were used to create four yearly cohorts, 2007-2010, including all eligible prevalent patients on hemodialysis in the United States on January 1 of each year. A secondary analysis comprising patients in a large dialysis organization conducted over the same period permitted inclusion of patient-level markers of mineral metabolism. Patients were grouped into 10 regions designated by the Centers for Medicare and Medicaid Services and divided by latitude into one of three bands: south,35°; middle, 35° to40°; and north, ≥40°. Poisson regression was used to calculate unadjusted and adjusted region-level rate ratios for events.Overall, 327,615 patients on hemodialysis were included. Mean (SD) age was 61.8 (15.0) years old, 52.7% were white, and 55.0% were men. During 716,962 person-years of follow-up, 44,014 fractures and tendon ruptures occurred, the latter being only 0.3% of overall events. Event rates ranged from 5.36 to 7.83 per 100 person-years, a 1.5-fold rate difference across regions. Unadjusted region-level rate ratios varied from 0.83 (95% confidence interval, 0.81 to 0.85) to 1.20 (95% confidence interval, 1.18 to 1.23), a 1.45-fold rate difference. After adjustment for a wide range of case mix variables, a 1.33-fold variation in rates remained. Rates were higher in north and middle bands than the south (north rate ratio, 1.18; 95% confidence interval, 1.13 to 1.23; middle rate ratio, 1.13; 95% confidence interval, 1.10 to 1.17). Latitude explained 11% of variation, independent of region. A complementary analysis of 87,013 patients from a large dialysis organization further adjusted for circulating mineral metabolic parameters and protein energy wasting yielded similar results.Rates of fractures vary geographically in the United States dialysis population, even after adjustment for known patient characteristics. Latitude seems to contribute to this phenomenon, but additional analyses exploring whether other factors might influence variation are warranted.

Purpose When medications are modified in response to changing clinical conditions, confounding by indication arises that cannot be controlled using traditional adjustment. Inverse probability of treatment weights (IPTWs) can address this confounding given assumptions of no unmeasured confounders and that all patients have a positive probability of receiving all levels of treatment (positivity). We sought to explore these assumptions empirically in the context of epoetin-alfa (EPO) dosing and mortality. Methods We developed a single set of IPTWs for seven EPO dose categories and evaluated achieved covariate balance, mortality hazard ratios, and confidence intervals using two levels of treatment model parameterization and weight deletion. Results We found that IPTWs improved covariate balance for most confounders, but was not optimal for prior hemoglobin. Including more predictors in the treatment model or retaining highly weighted individuals resulted in estimates closer to the null, although precision decreased. Conclusion We chose to evaluate weights and covariate balance at a single time-point to facilitate an empirical analysis of model assumptions. These same assumptions are applicable to a time-dependent analysis, although empirical examination is not straight forward in that case. We find that the inclusion of rare treatment decisions and the high weights that result is needed for covariate balance under the positivity assumption. Removal of these influential weights can result in bias in either direction relative to the original confounding. It is therefore important to determine the reason for these rare patterns and whether inference is possible for all treatment levels. Copyright © 2012 John Wiley & Sons, Ltd.

The contribution of albuminuria to the increased risk of incident end-stage renal disease (ESRD) in individuals with a family history of ESRD has not been well studied.Prospective cohort study. STUDY SETTINGPARTICIPANTS: We analyzed data for family history of ESRD collected from 19,409 participants of the Renal REGARDS (Reasons for Geographic and Racial Differences in Stroke) cohort study.Family history of ESRD was ascertained by asking "Has anyone in your immediate family ever been told that he or she had kidney failure? This would be someone who is on or had been on dialysis or someone who had a kidney transplant."Incidence rate for ESRD.Morning urine albumin-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR). Incident cases of ESRD were identified through the US Renal Data System.A family history of ESRD was reported by 11.1% of participants. Mean eGFRs for those with and without a family history of ESRD were 87.5 ± 22.2 (SD) and 86.5 ± 19.3 mL/min/1.73 m(2), respectively (P = 0.05) and the respective geometric mean ACRs were 12.2 and 9.7 mg/g (P0.001). ESRD incidence rates for those with and without a family history of ESRD were 244.3 and 106.1/100,000 person-years, respectively. After adjusting for age, sex, and race, the ESRD HR for those with versus those without a family history of ESRD was 2.13 (95% CI, 1.18-3.83). Adjustment for comorbid conditions and socioeconomic status attenuated this association (HR, 1.82; 95% CI, 1.00-3.28), and further adjustment for baseline eGFR and ACR completely attenuated the association between family history of ESRD and incident ESRD (HR, 1.12; 95% CI, 0.69-1.80).The report of a family history of ESRD was not validated.Family history of ESRD is common in older Americans and the increased risk of ESRD associated with a family history reflects lower GFR, higher albuminuria, and comorbid conditions.

Hemodialysis patients who live at high altitude use less exogenous erythropoietin but achieve higher hematocrit levels than those living at a lower altitude. The authors hypothesized that the effect of altitude would be strongest in hemodialysis patients with poor anemia treatment response. To explore this hypothesis, they studied anemia-related outcomes in US hemodialysis patients who move to higher altitudes. Using Medicare and US Geological Survey data, in 1992–2004 they identified instances in which a patient moved from a dialysis center at an altitude of

Background Substantial variability in hemoglobin levels has been associated with increased mortality risk in hemodialysis patients. Variability also has been associated with concurrent comorbid conditions and hospitalization. Adequate adjustment for confounding by disease severity is needed to estimate the association of hemoglobin level variability with mortality risk. Study Design Retrospective cohort study. Setting & Participants Medicare hemodialysis patients in 3 groups: prevalent on July 1, 2006 (n = 133,246), prevalent on July 1, 1996 (n = 78,602), and incident between January 1, 2005, and June 30, 2006 (n = 24,999). Predictor Hemoglobin level variability estimated using the residual deviation around the linear trend in hemoglobin levels during a 6-month entry period. Outcome Time to death. Measurements We fit Cox models of 1-year mortality with and without adjustment for disease severity (comorbid conditions, hospitalization days, and months with hemoglobin level Results Disease severity was associated positively with hemoglobin level variability in all groups. Before adjustment for disease severity, HRs for hemoglobin level variability were 1.27 (95% CI, 1.24-1.31) per 1 g/dL for patients prevalent in 2006, 1.32 (95% CI, 1.27-1.38) for patients prevalent in 1996, and 1.08 (95% CI, 1.03-1.13) for patients incident in 2005-2006. After adjustment, HRs for hemoglobin level variability were 1.02 (95% CI, 0.99-1.05), 1.07 (95% CI, 1.03-1.12), and 1.01 (95% CI, 0.95-1.06), respectively. Limitations We did not adjust for time-varying confounding of hemoglobin level; an inclusion requirement introduces potential selection bias; our findings may not apply to incident hemodialysis patients younger than 65 years; assessment of comorbid conditions from claims is subject to misclassification, with possible residual confounding attributable to comorbid conditions; this observational study cannot prove causality. Conclusions After adjustment for concurrent disease severity, evidence supporting an association between hemoglobin level variability and mortality risk was weak and inconsistent. The clinical utility of hemoglobin level variability may be limited.

Background Recent clinical trials in cancer patients treated with erythropoiesis-stimulating agents (ESAs) and in CKD patients treated to haemoglobin (Hb) targets above the labeled range of 10-12 g/dL with ESAs raised safety concerns regarding ESA therapy. Subsequently, product labeling was revised including addition of a black-box warning and removal of many quality of life claims not supported by current standards, and there were changes in reimbursement and anaemia guidelines. The extent to which these events influenced ESA dosing and Hb levels in patients with chronic kidney disease not on dialysis (CKD-NOD) is not known. Methods We used data collected in a series of cross-sectional surveys between March 2005 and July 2009. Patients with CKD-NOD were selected from a random sample of free-standing US nephrology clinics. Information on demographics, insurance information, laboratory data and ESA use was abstracted from medical records by site investigators. We evaluated ESA treatment (use and dosing) and Hb levels over time and used multivariate linear regression to assess changes in ESA doses and Hb levels over time adjusting for case-mix differences. Results Between 2005 and 2009, 15 836 CKD-NOD patients were sampled. During this period, ESA use declined from 60 to 46%, and the mean dose declined from 176 to 136 mcg/month; the largest decline in use and in dose occurred beginning in 2007. Simultaneously, the mean (standard deviation) Hb level in ESA-treated patients declined from 11.5 (1.4) to 10.6 (1.2) g/dL, though the decline was most pronounced starting in 2007. As the mean Hb declined, the percent of treated patients with an Hb > 12 g/dL dropped from 27 to 12%, and the mean dose in this sub-population declined from 173 to 111 mcg/month. Conclusion The emergence of safety concerns and the subsequent changes in product labeling, reimbursement and clinical practice guidelines all appear to have influenced physician dosing practices resulting in less frequent use of ESAs, lower ESA doses and lower achieved Hb levels in CKD-NOD patients.

The severity of anemia at which to initiate erythropoiesis-stimulating agent (ESA) treatment in nondialysis chronic kidney disease (CKD) patients is unclear. Risk of mortality, hospitalizations, and blood transfusion were compared among nondialysis CKD patients with "early" versus "delayed" ESA initiation.A retrospective cohort study was conducted on CKD (estimated GFR60 ml/min/1.73m(2)) outpatients in the national Veterans Administration who were initiated on ESAs. Patients with ESRD, gastrointestinal bleeding, chemotherapy, or hematologic malignancy were excluded. Patients were characterized as having early [hemoglobin (Hb) 10.0 to 11.0 g/dl] or delayed (Hb 8.0 to 9.9 g/dl) ESA initiation. A propensity score comprising demographic, clinical, and laboratory variables was used to select a 1:1 matched cohort. Cox survival and negative binomial regression were used to compare the matched groups for all-cause mortality, hospitalizations, and blood transfusions.Of 1837 patients who met inclusion criteria, 1410 (77%) were successfully matched. The groups did not differ significantly in 31 characteristics reflecting sociodemographics, comorbidity, healthcare utilization, and renal function. There was no significant difference in mortality with early initiation. Those initiated early had a 17% lower risk of initial hospitalization and a 29% lower risk of transfusion compared with delayed initiation patients. Results did not differ between those with and without pre-ESA transfusion or hospitalization.In nondialysis CKD, ESA initiation at Hb 10.0 to 11.0 g/dl compared with 8.0 to 9.9 g/dl is associated with reduced risk of blood transfusion and initial hospitalization.

Although well-described for patients who require dialysis, information on transfusion burden related to anemia in the nondialysis patient population with chronic kidney disease (CKD) is lacking.A retrospective study was conducted of patients with CKD and chronic anemia from 2002 through 2007 in the Veterans Administration Healthcare System. Included patients had stage 3 CKD or higher and anemia (one or more hemoglobin [Hb] levels11 g/dl or received anemia therapy [erythropoiesis-stimulating agents [ESAs], iron, or both]). The outcome of interest was transfusion events, which was evaluated in relation to the absolute Hb level and changes in Hb levels overall and according to the type of treatment received (no treatment, iron therapy, ESA therapy, or ESA and iron therapy) concurrent with each Hb measurement.Among 97,636 patients with CKD and anemia, we observed 68,556 transfusion events (61 events per 100 person-years), 86.6% of which occurred in inpatient settings. At all Hb levels, transfusion events were highest during periods of no treatment and increased with declining Hb levels. Between an Hb of 10.0 and 10.9 g/dl, the transfusion rate was 2.0% for those who received an ESA, iron, or both and 22% for those who received no treatment; at an Hb level of 7.0 to 7.9 g/dl, the transfusion rate was 10 to 12% for treated and 58% for untreated patients. Low absolute Hb levels but not Hb changes was most predictive of a transfusion even after adjustment for patient case mix.Transfusions are still used to treat anemia in patients who have CKD and do not require dialysis, although they occur considerably less frequently in patients who receive other available anemia therapies.

Background and objectives: Observational studies relating epoetin alfa (EPO) dose and mortality frequently use analytic methods that do not control time-dependent confounding by indication (CBI). The relationship between EPO dose and 1-year mortality, adjusting for the effects of time-dependent CBI, was examined using a marginal structural model. Design, setting, participants, & measurements: This retrospective cohort study included 27,791 hemodialysis patients between July 2000 and June 2002. Patients were grouped at successive 2-wk intervals into a zero-dose category or four nonzero-dose categories. Ordinal regression was used to calculate inverse probability of treatment weights of patients receiving their own dose level given their covariate and treatment history. Three treatment models with an increasing number of treatment predictors were evaluated to assess the effect of model specification. A small number of excessively large patient weights were truncated. Relative hazards for higher-dose groups compared with the lowest nonzero-dose group varied by treatment model specification and by level of weight truncation. Results: Results differed appreciably between the simplest treatment model, which incorporated only hemoglobin and EPO dosing history with 2% weight truncation (hazard ratio: 1.51; 95% confidence interval: 1.09, 1.89 for highest-dose patients), and the most comprehensive treatment model with 1% weight truncation (hazard ratio: 0.98; 95% confidence interval: 0.76, 1.74). Conclusions: There is appreciable CBI at higher EPO doses, and EPO dose was not associated with increased mortality in marginal structural model analyses that more completely addressed this confounding.

SUMMARY Purpose WeexaminedtheassociationbetweenhighdosesofEpoetinalfa(EPO),whichareusedtoraiseandmaintainhemoglobin(Hb)levelswithin target ranges for hemodialysis patients, and short-term mortality risk using multivariable regression and an instrumental variable (IV)analysis.Methods We identified 32734 patients receiving hemodialysis in 786 facilities from a large US dialysis provider between July 2000 andMarch2002whoreceivedcarefor>4consecutivemonths,andhadanHb 25%(instrument). Weassessed deathsduring the subsequent 90 days and evaluated the EPO dose-mortality association using conventional linear and IV regression.Results Thestudypopulationhadamean(SD)ageof60.4(15.0)years;48%werewhite,42%wereblackand51%weremale.Inunadjustedanalyses,highEPOdoseswereassociatedwith90-daymortalityrisk(RiskDifference,RD¼3.0per100persons,95%CI:2.3–3.6);mortalityrisk was attenuated after adjustment for confounding (RD¼1.5 per 100 persons, 95%CI:0.8–2.2) and not associated with high EPO dose inthe pooled IV analysis, though confidence intervals (CI) were wide (RD¼ 0.4 per 100 persons, 95%CI:-3.2-2.4).Conclusions The difference in risk estimates between the adjusted linear regression and the IV regression suggests that the short-termmortality related to EPO dosing may be largely attributable to confounding-by-indication for higher doses. The IV method, which wasemployed to address the possibility of residual confounding, yielded near null though imprecise effect estimates. Copyright # 2009 JohnWiley & Sons, Ltd.key words—Epoetin alfa; hemodialysis; anemia; mortality; confounding-by-indicationReceived 27 November 2008; Revised 15 May 2009; Accepted 1 June 2009

Background: Anemia is a common complication of chronic kidney disease (CKD), but anemia treatment may be less comprehensive than guidelines suggest. Methods: The study population (n = 11,754) included general Medicare recipients with Parts A and B coverage before January 1, 2001, aged ≥65 years on January 1, 2001, and alive with Medicare as primary payer through December 31, 2001. Time-dependent proportional hazards models were used to investigate predictors of erythropoiesis-stimulating agent (ESA) use, adjusted for comorbid conditions and severity-of-disease variables as time-dependent, and age, sex, and race as fixed variables. ESA use was defined during 2002 and time-dependent variables during 2001–2002. Results: Only 839 patients (7%) received ESAs. Characteristics significantly predictive of ESA use (p < 0.05) were: outpatient specialty services, nephrology and hematology/oncology/medical oncology (RR 6.92); outpatient specialty services, hematology/oncology/medical oncology (RR 6.02); outpatient specialty services, nephrology (RR 3.44); inpatient principle procedure, other operations on vessels (RR 1.68); transfusions (RR 1.54), hypertension (RR 1.50); congestive heart failure (RR 1.34); home oxygen (RR 1.28). Conclusions: Access to anemia treatment may be an important marker for access to CKD care. Clinical trials are needed to assess effects of early referral and more comprehensive anemia treatment.

Background: Chronic kidney disease (CKD) is a prevalent condition; however, little is known about healthcare resource utilization (HRU) by CKD patients. Methods: This analysis included NHANES participants aged ≥18 years, with serum creatinine, urine protein, and hemoglobin measurements. We assessed the association between CKD (stratified by stage) and HRU based on self-reported physician visits and hospitalizations in the year preceding the survey. Results: Of the 15,258 included in this analysis, 2,110 had early CKD (stage 1 and 2 CKD) and 1,121 had late CKD (stage 3 and 4 CKD). Mean (SE) number of annual physician visits were 3.51 (0.08), 4.43 (0.18), and 6.53 (0.38) for participants with no CKD, early CKD, and late CKD, respectively. Mean (SE) number of annual hospitalizations were 0.15 (0.01), 0.19 (0.01), and 0.42 (0.03) for participants with no CKD, early CKD, and late CKD, respectively. Participants with late CKD were more likely to have more physician visits (OR 1.81, 95% CI 1.46, 2.23) and have more hospital admissions (OR 2.12, 95% CI 1.66, 2.71) compared with participants with early CKD or no CKD. Conclusions: In this analysis, late stage CKD was associated with increased HRU, suggesting the need for early identification and treatment of CKD and its associated conditions.

Background Inflammation in an ESRD patient may impact responsiveness to erythropoiesis-stimulating agent (ESA) therapy. We sought to investigate the association between C-reactive protein (CRP) levels and average per-administration epoetin alfa (EPO) dose over 3 months following a CRP measurement. Methods The study is a retrospective cohort study of hemodialysis patients >or=18 years of age receiving care at a Fresenius Medical Care-North America facility between 1 July 2000 and 30 June 2002 who had no history of peritoneal dialysis. All patients had >or=1 CRP measurement and >or=3 months of recorded information before the CRP measurement (entry period). We evaluated the association between CRP levels and average hemoglobin (Hb) and per-administration EPO dose over the 3 months following the CRP measurement. Results We identified 1754 patients with a CRP measurement; mean age was 62.6 years (SD 14.1), 51.5% were male, 56.2% were white and the median CRP value was 2.04 mg/dL (20.4 mg/L). Patients in the upper CRP quartiles were more likely to be older, recently hospitalized; have a catheter vascular access; have lower albumin, Hb and transferrin saturation levels and greater EPO doses. In the subsequent 3 months, EPO doses but not Hb levels were significantly higher for patients in the highest CRP quartile [3.21 mg/dL (32.1 mg/L)] (P = 0.01). Conclusions Inflammation as measured by an elevated CRP level appears to be an independent predictor of greater ESA dose requirements. Patients with the highest CRP levels required significantly higher ESA doses to achieve comparable Hb levels even after controlling for potential confounding variables.

Background and objectives: Among hemodialysis patients, achieved hemoglobin is associated with Epoetin alfa dose and erythropoietin responsiveness. A prospective erythropoietin responsiveness measure was developed and its association with mortality evaluated. Design, setting, participants, & measurements: Data from 321 participants were used and randomized to the hematocrit normalization arm of the Normal Hematocrit Cardiac Trial. Subjects were to receive a 50% Epoetin alfa dose increase at randomization. The prospective erythropoietin responsiveness measure was defined as the ratio of weekly hematocrit change (over the 3 wk after randomization) per Epoetin alfa dose increase (1000 IU/wk) corresponding to the mandated 50% dose increase at randomization. The distribution of responsiveness was divided into quartiles. Over a 1-yr follow-up, Cox proportional hazard modeling evaluated associations between this responsiveness measure and mortality. Results: Erythropoietin responsiveness values ranged from −2.1% to 2.4% per week per 1000 IU. Although subjects were similar across response quartiles, mortality ranged between 14% and 34% among subjects in the highest and lowest response quartiles (P = 0.0004), respectively. After adjusting for baseline prognostic indicators, highest versus lowest responsiveness was associated with a hazard ratio of 0.41 (95% confidence interval, 0.20 to 0.87). Conclusion: Lower erythropoietin responsiveness is a strong, independent predictor of mortality risk and should be considered when evaluating associations between clinical outcomes and potential prognostic indicators, such as Epoetin alfa dose and achieved hemoglobin values.

Missed in-center hemodialysis treatments (MHT) are a general indicator of health status in hemodialysis patients. This analysis was conducted to estimate the association between cinacalcet use and MHT rate.We studied patients receiving hemodialysis and prescription benefits services from a large dialysis organization. Incident cinacalcet users were propensity score matched to controls on 31 demographic, clinical, and laboratory variables. We applied inverse probability (IP) of censoring and crossover weights to account for informative censoring. Weighted negative binomial modeling was used to estimate MHT rates and pooled logistics models were used to estimate the association between cinacalcet use and MHT.Baseline demographic and clinical variables included serum calcium, phosphorus, parathyroid hormone, and vitamin D use, and were balanced between 15,474 new cinacalcet users and 15,474 matched controls. In an analysis based on intention-to-treat principles, 40.8% of cinacalcet users and 46.5% of nonusers were censored. MHT rate was 13% lower among cinacalcet initiators versus controls: IP of censoring weighted incidence rate ratio was 0.87 (95% confidence interval [CI]: 0.84-0.90 p 0.001). In analyses based on as-treated principles, 72.8% and 61.5% of cinacalcet users and nonusers, respectively, crossed over or were censored. MHT rate was 15% lower among cinacalcet initiators versus controls: IP of censoring/crossover weighted incidence rate ratio was 0.85 (95%CI: 0.82-0.87 p 0.001).After controlling for indication and differential censoring, cinacalcet treatment was associated with lower MHT rates, which may reflect better health status. Copyright © 2016 John WileySons, Ltd.

Little is known about epoetin alfa (EPO) dosing at dialysis centers after implementation of the US Medicare prospective payment system and revision of the EPO label in 2011.Retrospective cohort study.Approximately 412,000 adult hemodialysis patients with Medicare Parts A and B as primary payer in 2009 to 2012 to describe EPO dosing and hemoglobin patterns; of these, about 70,000 patients clustered in about 1,300 dialysis facilities to evaluate facility-level EPO titration practices and patient-level outcomes in 2012.Facility EPO titration practices when hemoglobin levels were 10 and11g/dL (grouped treatment variable) determined from monthly EPO dosing and hemoglobin level patterns.Patient mean hemoglobin levels, red blood cell transfusion rates, and all-cause and cause-specific hospitalization rates using a facility-based analysis.Monthly EPO dose and hemoglobin level, red blood cell transfusion rates, and all-cause and cause-specific hospitalization rates.Monthly EPO doses declined across all hemoglobin levels, with the greatest decline in patients with hemoglobin levels 10g/dL (July-October 2011). In 2012, nine distinct facility titration practices were identified. Across groups, mean hemoglobin levels differed slightly (10.5-10.8g/dL) but within-patient hemoglobin standard deviations were similar (∼0.68g/dL). Patients at facilities implementing greater dose reductions and smaller dose escalations had lower hemoglobin levels and higher transfusion rates. In contrast, patients at facilities that implemented greater dose escalations (and large or small dose reductions) had higher hemoglobin levels and lower transfusion rates. There were no clinically meaningful differences in all-cause or cause-specific hospitalization events across groups.Possibly incomplete claims data; excluded small facilities and those without consistent titration patterns; hemoglobin levels reported monthly; inferred facility practice from observed dosing.Following prospective payment system implementation and labeling revisions, EPO doses declined significantly. Under the new label, facility EPO titration practices were associated with mean hemoglobin levels (but not standard deviations) and transfusion use, but not hospitalization rates.

The role of obesity in prostate cancer etiology remains controversial. A recent report suggested that obese men younger than age 60 may have a lower risk of developing prostate cancer than men the same age who are not obese. The current study used a nested, matched case-control study design and data collected in the General Practice Research Database between January 1991 and December 2001 to assess the association between body mass index (BMI) and the risk of incident prostate cancer. Seven hundred and thirty cases of prostate cancer with adequate information on BMI were identified and matched to 2740 controls on age, sex, general practice, and index date. Obese men (BMIor = 30.0 kilograms [kg]/square of height in meters [m(2)]) were at lower risk of developing prostate cancer (AOR=0.78, 95% CI: 0.56, 1.09) compared to normal weight men (BMI=23.0-24.9 kg/m(2)), and the data best fit an inverse quadratic model for the relation between BMI and the risk of prostate cancer. This study provides modest support for a protective association between obesity and the risk of incident prostate cancer.