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Rationale & Objective: Matrix metalloproteinase 2 (MMP-2) plays an important role in the development of fibrosis, the final common pathway of chronic kidney disease (CKD). This study aimed to assess the relationship between repeated measures of MMP-2 and CKD progression in a large, diverse prospective cohort. Study Design: In a prospective cohort of Chronic Renal Insufficiency Cohort (CRIC) participants (N = 3,827), MMP-2 was measured at baseline. In a case-cohort design, MMP-2 was additionally measured at year 2 in a randomly selected subcohort and cases of estimated glomerular filtration rate (eGFR) halving or kidney replacement therapy (KRT) (N = 1,439). Setting & Participants: CRIC is a multicenter prospective cohort of adults with CKD. Exposure: MMP-2 measured in plasma at baseline and at year 2. Outcomes: A composite kidney endpoint (KRT/eGFR halving) Analytical Approach: Weighted Cox proportional hazards models for case-cohort participants. Results: Participants were followed for a median of 4.6 years from year 2 and 6.9 years from the baseline. Persistently elevated MMP-2 (≥300 ng/mL at both baseline and year 2) increased the hazard of the composite kidney endpoint (HR, 1.61; 95% CI, 1.07-2.42; P = 0.09) after adjusting for covariates. The relationship of persistently elevated MMP-2 was modified by levels of inflammation, with a 2.6 times higher rate of the composite kidney endpoint in those with high-sensitivity C-reactive protein

Rationale & Objective: The extent to which depression affects the progression of chronic kidney disease (CKD) and leads to adverse clinical outcomes remains inadequately understood. We examined the association of depressive symptoms (DS) and antidepressant medication use on clinical outcomes in 4,839 adults with nondialysis CKD. Study Design: Observational cohort study. Setting and Participants: Adults with mild to moderate CKD who participated in the multicenter Chronic Renal Insufficiency Cohort Study (CRIC). Exposure: The Beck Depression Inventory (BDI) was used to quantify DS. Antidepressant use was identified from medication bottles and prescription lists. Individual effects of DS and antidepressants were examined along with categorization as follows: (1) BDI

Rationale & Objective: This study aimed to assess the effect of exposure to organic pollutants in adults with chronic kidney disease (CKD). Study Design: This was a cross-sectional and longitudinal analysis. Setting and Participants: Forty adults enrolled in the Chronic Renal Insufficiency Cohort (CRIC). Exposures: Exposure at baseline and longitudinally to various organic chemical pollutants. Outcomes: The outcomes were as follows: death; composite of congestive heart failure, myocardial infarction, and stroke; event-free survival from kidney failure or ≥50% decline in estimated glomerular filtration rate (eGFR); and longitudinal trajectory of eGFR. Analytical Approach: We used high-performance liquid chromatography with tandem mass spectrometry to measure urinary concentrations of bisphenols, phthalates, organophosphate pesticides, polycyclic aromatic hydrocarbons, melamine, and cyanuric acid at years 1, 3, and 5 after enrollment in the CRIC. Univariate and multivariable logistic regression were used to examine the association of individual compounds and classes of pollutants with the outcomes. The Cox proportional hazards model and Kaplan-Meier method were used to calculate hazard ratios and 95% CIs for each class of pollutants. Results: Median baseline eGFR and urinary protein-to-creatinine ratio were 33 mL/min/1.73 m2 and 0.58 mg/g, respectively. Of 52 compounds assayed, 30 were detectable in ≥50% of participants. Urinary chemical concentrations were comparable in patients with CKD and healthy individuals from contemporaneous National Health and Nutrition Examination Survey cohorts. Phthalates were the only class with a trend toward higher exposure in patients with CKD. There was an inverse relationship between exposure and the eGFR slopes for bisphenol F, mono-(3-carboxypropyl) phthalate, mono-benzyl phthalate, mono-[2-(carboxymethyl)hexyl] phthalate, and melamine. There were no associations between organic pollutant exposure and cardiovascular outcomes. Limitations: Small sample size, evaluation of single rather than combined exposures. Conclusions: Simultaneous measurement of multiple organic pollutants in adults with CKD is feasible. Exposure levels are comparable with healthy individuals. Select contaminants, especially in the phthalate class, may be associated with more rapid deterioration in kidney function. Plain-Language Summary: The effect of exposure to organic pollutants has not been studied in adults with chronic kidney disease. (CKD). To fill this gap, we measured the exposure to a wide range of chemicals that are found in plastics, personal care products, and food preparation. Overall, the exposure was similar to that noted in the healthy population living in the United States. Only select compounds, mainly phthalates, demonstrated a trend with a more rapid decline in kidney function. These findings provide a useful reference for future studies that aim to evaluate organic pollutant exposure in patients with CKD. This is significant because these exposures represent a modifiable risk factor for disease progression through alterations in diet or lifestyle.

Rationale & Objective: Heart failure (HF) is an important cause of morbidity and mortality among individuals with chronic kidney disease (CKD). A large body of evidence from preclinical and clinical studies implicates excess levels of fibroblast growth factor 23 (FGF23) in HF pathogenesis in CKD. It remains unclear whether the relationship between elevated FGF23 levels and HF risk among individuals with CKD varies by HF subtype. Study Design: Prospective cohort study. Settings & Participants: A total of 3,502 participants were selected in the Chronic Renal Insufficiency Cohort study. Exposure: Baseline plasma FGF23. Outcomes: Incident HF by subtype and total rate of HF hospitalization. HF was categorized as HF with preserved ejection fraction (HFpEF, ejection fraction [EF] ≥ 50%), HF with reduced EF (HFrEF, EF

Diabetic kidney disease (DKD) can lead to end-stage kidney disease (ESKD) and mortality; however, few mechanistic biomarkers are available for high-risk patients, especially those without macroalbuminuria. Urine from participants with diabetes from the Chronic Renal Insufficiency Cohort (CRIC) study, the Singapore Study of Macro-angiopathy and Micro-vascular Reactivity in Type 2 Diabetes (SMART2D), and the American Indian Study determined whether urine adenine/creatinine ratio (UAdCR) could be a mechanistic biomarker for ESKD. ESKD and mortality were associated with the highest UAdCR tertile in the CRIC study and SMART2D. ESKD was associated with the highest UAdCR tertile in patients without macroalbuminuria in the CRIC study, SMART2D, and the American Indian study. Empagliflozin lowered UAdCR in nonmacroalbuminuric participants. Spatial metabolomics localized adenine to kidney pathology, and single-cell transcriptomics identified ribonucleoprotein biogenesis as a top pathway in proximal tubules of patients without macroalbuminuria, implicating mTOR. Adenine stimulated matrix in tubular cells via mTOR and stimulated mTOR in mouse kidneys. A specific inhibitor of adenine production was found to reduce kidney hypertrophy and kidney injury in diabetic mice. We propose that endogenous adenine may be a causative factor in DKD.

Background The ratio of 24,25‐dihydroxyvitamin D3/25‐hydroxyvitamin D3 (vitamin D metabolite ratio [VDMR]) may reflect functional vitamin D activity. We examined associations of the VDMR, 25‐hydroxyvitamin D (25[OH]D), and 1,25‐dihydroxyvitamin D (1,25[OH]2D) with cardiovascular disease (CVD) in patients with chronic kidney disease. Methods and Results This study included longitudinal and cross‐sectional analyses of 1786 participants from the CRIC (Chronic Renal Insufficiency Cohort) Study. Serum 24,25‐dihydroxyvitamin D3, 25(OH)D, and 1,25(OH)2D were measured by liquid chromatography–tandem mass spectrometry 1 year after enrollment. The primary outcome was composite CVD (heart failure, myocardial infarction, stroke, and peripheral arterial disease). We used Cox regression with regression‐calibrated weights to test associations of the VDMR, 25(OH)D, and 1,25(OH)2D with incident CVD. We examined cross‐sectional associations of these metabolites with left ventricular mass index using linear regression. Analytic models adjusted for demographics, comorbidity, medications, estimated glomerular filtration rate, and proteinuria. The cohort was 42% non‐Hispanic White race and ethnicity, 42% non‐Hispanic Black race and ethnicity, and 12% Hispanic ethnicity. Mean age was 59 years, and 43% were women. Among 1066 participants without prevalent CVD, there were 298 composite first CVD events over a mean follow‐up of 8.6 years. Lower VDMR and 1,25(OH)2D were associated with incident CVD before, but not after, adjustment for estimated glomerular filtration rate and proteinuria (hazard ratio, 1.11 per 1 SD lower VDMR [95% CI, 0.95–1.31]). Only 25(OH)D was associated with left ventricular mass index after full covariate adjustment (0.6 g/m2.7 per 10 ng/mL lower [95% CI, 0.0–1.3]). Conclusions Despite modest associations of 25(OH)D with left ventricular mass index, 25(OH)D, the VDMR, and 1,25(OH)2D were not associated with incident CVD in chronic kidney disease.

Rationale and Objective: Chronic kidney disease is a risk enhancing factor for cardiovascular disease (CVD) and mortality, and the role of aspirin use is unclear in this population. We investigated the risk and benefits of aspirin use in primary and secondary prevention of CVD in the Chronic Renal Insufficiency Cohort Study. Study Design: Prospective observational cohort. Setting & Participants: 3,664 Chronic Renal Insufficiency Cohort participants. Exposure: Aspirin use in patients with and without preexisting CVD. Outcomes: Mortality, composite and individual CVD events (myocardial infarction, stroke, and peripheral arterial disease), kidney failure (dialysis and transplant), and major bleeding. Analytical Approach: Intention-to-treat analysis and multivariable Cox proportional hazards model to examine associations of time varying aspirin use. Results: The primary prevention group was composed of 2,578 (70.3%) individuals. Mean age was 57 ± 11 years, 46% women, 42% Black, and 47% had diabetes. The mean estimated glomerular filtration rate was 45 mL/min/1.73 m2. Median follow-up was 11.5 (IQR, 7.4-13) years. Aspirin was not associated with all-cause mortality in those without preexisting cardiovascular disease (CVD) (HR, 0.84; 95% CI, 0.7-1.01; P = 0.06) or those with CVD (HR, 0.88; 95% CI, 0.77-1.02, P = 0.08). Aspirin was not associated with a reduction of the CVD composite in primary prevention (HR, 0.97; 95% CI, 0.77-1.23; P = 0.79) and in secondary prevention because the original study design was not meant to study the effects of aspirin. Limitations: This is not a randomized controlled trial, and therefore, causality cannot be determined. Conclusions: Aspirin use in chronic kidney disease patients was not associated with reduction in primary or secondary CVD events, progression to kidney failure, or major bleeding.

BACKGROUND Metabolomic profiling in individuals with chronic kidney disease (CKD) has the potential to identify novel biomarkers and provide insight into disease pathogenesis.METHODS We examined the association between blood metabolites and CKD progression, defined as the subsequent development of end-stage renal disease (ESRD) or estimated glomerular filtrate rate (eGFR) halving, in 1,773 participants of the Chronic Renal Insufficiency Cohort (CRIC) study, 962 participants of the African-American Study of Kidney Disease and Hypertension (AASK), and 5,305 participants of the Atherosclerosis Risk in Communities (ARIC) study.RESULTS In CRIC, more than half of the measured metabolites were associated with CKD progression in minimally adjusted Cox proportional hazards models, but the number and strength of associations were markedly attenuated by serial adjustment for covariates, particularly eGFR. Ten metabolites were significantly associated with CKD progression in fully adjusted models in CRIC; 3 of these metabolites were also significant in fully adjusted models in AASK and ARIC, highlighting potential markers of glomerular filtration (pseudouridine), histamine metabolism (methylimidazoleacetate), and azotemia (homocitrulline). Our findings also highlight N-acetylserine as a potential marker of kidney tubular function, with significant associations with CKD progression observed in CRIC and ARIC.CONCLUSION Our findings demonstrate the application of metabolomics to identify potential biomarkers and causal pathways in CKD progression.FUNDING This study was supported by the NIH (U01 DK106981, U01 DK106982, U01 DK085689, R01 DK108803, and R01 DK124399).

Introduction: Management of chronic kidney disease (CKD) entails high medical complexity and often results in high hospitalization burden. There are limited data on the associations of longitudinal hospital utilization patterns with adverse clinical outcomes in individuals with CKD. Methods: We derived cumulative all-cause hospitalization trajectory groups using latent class trajectory analysis in 3012 participants of the Chronic Renal Insufficiency Cohort (CRIC) Study who were alive and did not reach end-stage kidney disease (ESKD) within 4 years of study entry. Cox proportional hazards models tested the associations between hospitalization trajectory groups and risks of ESKD and death prior to the onset of ESKD (ESKD-censored death). Results: Within 4 years of study entry, there were 5658 hospitalizations among 3012 participants. We identified 3 distinct subgroups of individuals with CKD based on cumulative all-cause hospitalization trajectories over 4 years: low-utilizer (n = 1066), intermediate-utilizer (n = 1802), and high-utilizer (n = 144). High-utilizers represented a patient population of lower socioeconomic status who had a greater prevalence of comorbid conditions and lower kidney function compared with intermediate- and low-utilizers. After the 4-year ascertainment period to form the trajectory subgroups, there were 544 ESKD events and 437 ESKD-censored deaths during a median follow-up time of 5.1 years. Compared with low-utilizers, intermediate-utilizers and high-utilizers were at 1.49-fold (95% confidence interval [CI] 1.22–1.84) and 1.75-fold (95% CI 1.20–2.56) higher risk of ESKD in adjusted analyses, respectively. Compared with low-utilizers, intermediate-utilizers and high-utilizers were at 1.48-fold (95% CI 1.17–1.87) and 2.58-fold (95% CI 1.74–3.83) higher risk of ESKD-censored death in adjusted analyses, respectively. Conclusions: Trajectories of cumulative all-cause hospitalization identify subgroups of individuals with CKD who are at high risk of ESKD and death.

Patients with chronic kidney disease are at risk of developing cardiovascular disease. To facilitate out-of-clinic evaluation, we piloted wearable device-based analysis of heart rate variability and behavioral readouts in patients with chronic kidney disease from the Chronic Renal Insufficiency Cohort and controls (n = 49). Time-specific partitioning of heart rate variability readouts confirm higher parasympathetic nervous activity during the night (mean RR at night 14.4 ± 1.9 ms vs. 12.8 ± 2.1 ms during active hours; n = 47, analysis of variance (ANOVA) q = 0.001). The α2 long-term fluctuations in the detrended fluctuation analysis, a parameter predictive of cardiovascular mortality, significantly differentiated between diabetic and nondiabetic patients (prominent at night with 0.58 ± 0.2 vs. 0.45 ± 0.12, respectively, adj. p = 0.004). Both diabetic and nondiabetic chronic kidney disease patients showed loss of rhythmic organization compared to controls, with diabetic chronic kidney disease patients exhibiting deconsolidation of peak phases between their activity and standard deviation of interbeat intervals rhythms (mean phase difference chronic kidney disease 8.3 h, chronic kidney disease/type 2 diabetes mellitus 4 h, controls 6.8 h). This work provides a roadmap toward deriving actionable clinical insights from the data collected by wearable devices outside of highly controlled clinical environments.

Background Deoxycholic acid (DCA) is a secondary bile acid that may promote vascular calcification in experimental settings. Higher DCA levels were associated with prevalent coronary artery calcification (CAC) in a small group of individuals with advanced chronic kidney disease. Whether DCA levels are associated with CAC prevalence, incidence, and progression in a large and diverse population of individuals with chronic kidney disease stages 2 to 4 is unknown. Methods and Results In the CRIC (Chronic Renal Insufficiency Cohort) study, we evaluated cross‐sectional (n=1057) and longitudinal (n=672) associations between fasting serum DCA levels and computed tomographic CAC using multivariable‐adjusted regression models. The mean age was 57±12 years, 47% were women, and 41% were Black. At baseline, 64% had CAC (CAC score >0 Agatston units). In cross‐sectional analyses, models adjusted for demographics and clinical factors showed no association between DCA levels and CAC >0 compared with no CAC (prevalence ratio per 1‐SD higher log DCA, 1.08 [95% CI, 0.91–1.26). DCA was not associated with incident CAC (incidence per 1‐SD greater log DCA, 1.08 [95% CI, 0.85–1.39]) or CAC progression (risk for increase in ≥100 and ≥200 Agatston units per year per 1‐SD greater log DCA, 1.05 [95% CI, 0.84–1.31] and 1.26 [95% CI, 0.77–2.06], respectively). Conclusions Among CRIC study participants, DCA was not associated with prevalent, incident, or progression of CAC.

Rationale & Objective: Having a usual source of care increases use of preventive services and is associated with improved survival in the general population. We evaluated this association in adults with chronic kidney disease (CKD). Study Design: Prospective, observational cohort study. Setting & Participants: Adults with CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study. Predictor: Usual source of care was self-reported as: 1) clinic, 2) emergency department (ED)/urgent care, 3) other. Outcomes: Primary outcomes included incident end-stage kidney disease (ESKD), atherosclerotic events (myocardial infarction, stroke, or peripheral artery disease), incident heart failure, hospitalization events, and all-cause death. Analytical Approach: Multivariable regression analyses to evaluate the association between usual source of care (ED/urgent care vs clinic) and primary outcomes. Results: Among 3,140 participants, mean age was 65 years, 44% female, 45% non-Hispanic White, 43% non-Hispanic Black, and 9% Hispanic, mean estimated glomerular filtration rate 50 mL/min/1.73 m2. Approximately 90% identified clinic as usual source of care, 9% ED/urgent care, and 1% other. ED/urgent care reflected a more vulnerable population given lower baseline socioeconomic status, higher comorbid condition burden, and poorer blood pressure and glycemic control. Over a median follow-up time of 3.6 years, there were 181 incident end-stage kidney disease events, 264 atherosclerotic events, 263 incident heart failure events, 288 deaths, and 7,957 hospitalizations. Compared to clinic as usual source of care, ED/urgent care was associated with higher risk for all-cause death (HR, 1.53; 95% CI, 1.05-2.23) and hospitalizations (RR, 1.41; 95% CI, 1.32-1.51). Limitations: Cannot be generalized to all patients with CKD. Causal relationships cannot be established. Conclusions: In this large, diverse cohort of adults with moderate-to-severe CKD, those identifying ED/urgent care as usual source of care were at increased risk for death and hospitalizations. These findings highlight the need to develop strategies to improve health care access for this high-risk population.

Abstract Background Chronic kidney disease (CKD) is an increasing epidemic globally that is associated with adverse health outcomes including end stage kidney disease (ESKD), cardiovascular disease (CVD), and death. American Indians (AIs) have a higher prevalence of CKD than most other racial/ethnic groups, due in part to a high prevalence of type 2 diabetes. Other genetic and environmental factors not yet identified may also contribute to the disproportionate burden of CKD in AIs. Method We will establish 3 clinical centers to recruit AIs from the Southwest United States (US) to expand the Chronic Renal Insufficiency Cohort (CRIC) study. We will follow the current CRIC protocol for kidney and cardiovascular measures and outcomes, which include ambulatory monitoring of kidney function and the use of mobile health technologies for CVD sub-phenotyping, and compare the outcomes in AIs with those in other racial/ethnic groups in CRIC. Discussion AI-CRIC will identify the role of various risk factors for rapid loss of kidney function among AIs of the Southwest US. In addition, to better understand the natural history of CKD and CVD in this high-risk population, we will identify unique risk factors for CKD and CVD progression in AIs. We will also compare event rates and risk factors for kidney and cardiovascular events in AIs with the other populations represented in CRIC.

Introduction: Subclinical changes to cardiac structure and function detected with echocardiography precede the development of clinical heart failure (HF) in persons with chronic kidney disease (CKD). Circulating cardiac biomarkers may reflect these pathophysiological changes. This study investigated associations between established biomarkers (N-terminal pro-B-type natriuretic peptide [NT-proBNP] and high-sensitivity troponin T [hsTnT]) and novel biomarkers (growth differentiation factor 15 [GDF-15], galectin-3 [Gal-3], and soluble ST-2 [sST-2]), using echocardiographic measurements in persons with CKD. Methods: In cross-sectional analyses among 2101 participants with mild to moderate CKD in the Chronic Renal Insufficiency Cohort (CRIC), biomarker levels measured at baseline were evaluated with echocardiographic measurements 1 year later. These included left ventricular mass index (LVMI), left ventricular end-systolic volume (LVESV), left ventricular end-diastolic volume (LVEDV), left ventricular ejection fraction (LVEF), and left atrial diameter (LAD). Multivariable linear regression analyses tested associations of each biomarker with echocardiographic measurements, adjusting for covariates. Results: GDF-15 was significantly associated with higher LVMI (1.0 g/m2.7; 95% CI, 0.4–1.7), LVESV (0.4 ml/m2.7; 95% CI, 0.0–0.7), and LVEDV (0.6 ml/m2.7; 95% CI, 0.1–1.1), but not with LVEF or LAD. These findings were not significant when adjusting for NT-proBNP and hsTnT. Gal-3 and sST-2 had no significant associations. Higher levels of NT-proBNP and hsTnT were associated with all echocardiographic measurements. Conclusion: In patients with CKD, the novel biomarker GDF-15, a marker of inflammation and tissue injury, and clinical biomarkers NT-proBNP and hsTnT, were associated with echocardiographic measurements of subclinical cardiovascular disease. Collectively, these biomarkers may highlight biological pathways that contribute to the development of clinical HF.

Rationale & Objective: Elevated levels of deoxycholic acid (DCA) are associated with adverse outcomes and may contribute to vascular calcification in patients with chronic kidney disease (CKD). We tested the hypothesis that elevated levels of DCA were associated with increased risks of cardiovascular disease, CKD progression, and death in patients with CKD. Study Design: Prospective observational cohort study. Setting & Participants: We included 3,147 Chronic Renal Insufficiency Cohort study participants who had fasting DCA levels. The average age was 59 ± 11 years, 45.3% were women, 40.6% were African American, and the mean estimated glomerular filtration rate was 42.5 ± 16.0 mL/min/1.73 m2. Predictor: Fasting DCA levels in Chronic Renal Insufficiency Cohort study participants. Outcomes: Risks of atherosclerotic and heart failure events, end-stage kidney disease (ESKD), and all-cause mortality. Analytical Approach: We used Tobit regression to identify predictors of DCA levels. We used Cox regression to examine the association between fasting DCA levels and clinical outcomes. Results: The strongest predictors of elevated DCA levels in adjusted models were increased age and nonuse of statins. The associations between log-transformed DCA levels and clinical outcomes were nonlinear. After adjustment, DCA levels above the median were independently associated with higher risks of ESKD (HR, 2.67; 95% CI, 1.51-4.74) and all-cause mortality (HR, 2.13; 95% CI, 1.25-3.64). DCA levels above the median were not associated with atherosclerotic and heart failure events, and DCA levels below the median were not associated with clinical outcomes. Limitations: We were unable to measure DCA longitudinally or in urinary or fecal samples, and we were unable to measure other bile acids. We also could not measure many factors that affect DCA levels. Conclusions: In 3,147 participants with CKD stages 2-4, DCA levels above the median were independently associated with ESKD and all-cause mortality.

Introduction: Assessment of impaired vitamin D metabolism is limited by lack of functional measures. CYP24A1-mediated vitamin D clearance, calculated as the ratio of serum 24,25-dihydroxyvitamin D3 to 25-hydroxyvitamin D3 (the vitamin D metabolic ratio, VDMR), is induced by 1,25-dihydroxyvitamin D and may assess tissue-level activity. We tested associations of the VDMR with risks of death and progression to end-stage renal disease (ESRD) in patients with chronic kidney disease (CKD). Methods: We studied participants from the Chronic Renal Insufficiency Cohort (CRIC), which included a random subset of 1080 CRIC participants plus additional participants who experienced ESRD or died (case cohort study design). Serum 24,25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3 was measured 1 year after enrollment. The primary outcomes included death and progression to ESRD. Using inverse probability weighting, we tested associations of VDMR (24,25[OH]2D3/25[OH]D3) with risks of death and ESRD, adjusting for demographics, comorbidity, and kidney function (estimated glomerular filtration rate [eGFR] and urine protein-to-creatinine ratio [PCR]). Results: There were a total of 708 ESRD events and 650 deaths events over mean (SD) follow-up periods of 4.9 (2.9) years and 6.5 (2.5) years, respectively. Lower VDMR was associated with increased risk of ESRD prior to adjusting for kidney function (hazard ratio [HR], 1.80 per 20 pg/ng lower VDMR; 95% confidence interval [CI], 1.56–2.08), but not with adjustment for kidney function (HR, 0.94 per 20 pg/ng; 95% CI, 0.81–1.10). Lower VDMR was associated with modestly increased mortality risk, including adjustment for kidney function (HR, 1.18 per 20 pg/ng; 95% CI, 1.02–1.36). Conclusion: Lower VDMR, a measure of CYP24A1-mediated vitamin D clearance, was significantly associated with all-cause mortality but not with progression to ESRD in patients with CKD. Keywords: kidney, mortality, vitamin D

Abstract Background Insulin resistance contributes to the metabolic syndrome, which is associated with the development of kidney disease. However, it is unclear if insulin resistance independently contributes to an increased risk of chronic kidney disease (CKD) progression or CKD complications. Additionally, predisposing factors responsible for insulin resistance in the absence of diabetes in CKD are not well described. This study aimed to describe factors associated with insulin resistance and characterize the relationship of insulin resistance to CKD progression, cardiovascular events and death among a cohort of non-diabetics with CKD. Methods Data was utilized from Chronic Renal Insufficiency Cohort Study participants without diabetes (N = 1883). Linear regression was used to assess associations with insulin resistance, defined using the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR). The relationship of HOMA-IR, fasting glucose, hemoglobin A1c (HbA1c), and C-peptide with CKD progression, cardiovascular events, and all-cause mortality was examined with Cox proportional hazards models. Results Novel positive associations with HOMA-IR included serum albumin, uric acid, and hemoglobin A1c. After adjustment, HOMA-IR was not associated with CKD progression, cardiovascular events, or all-cause mortality. There was a notable positive association of one standard deviation increase in HbA1c with the cardiovascular endpoint (HR 1.16, 95% CI: 1.00–1.34). Conclusion We describe potential determinants of HOMA-IR among a cohort of non-diabetics with mild-moderate CKD. HOMA-IR was not associated with renal or cardiovascular events, or all-cause mortality, which adds to the growing literature describing an inconsistent relationship of insulin resistance with CKD-related outcomes.

Introduction: A cornerstone of kidney disease management is participation in guideline-recommended health behaviors. However, the relationship of these health behaviors with outcomes, and the identification of barriers to health behavior engagement, have not been described among younger and older adults with chronic kidney disease. Methods: Data from a cohort study of 5499 individuals with chronic kidney disease was used to identify health behavior patterns with latent class analysis stratified by age

Rationale & Objective: Among individuals with chronic kidney disease (CKD), poor self-reported health is associated with adverse outcomes including hospitalization and death. We sought to examine the association between health-related quality-of-life (HRQoL) and depressive symptoms in advanced CKD and subsequent access to the kidney transplant waiting list. Study Design: Prospective cohort study. Setting & Population: 1,676 Chronic Renal Insufficiency Cohort (CRIC) study participants with estimated glomerular filtration rates ≤ 30 mL/min/1.73 m2 at study entry or during follow-up. Exposures: HRQoL ascertained by 5 scales of the Kidney Disease Quality of Life-36 Survey (Physical Component Summary [PCS], Mental Component Summary, Symptoms, Burdens, and Effects), with higher scores indicating better HRQoL, and depressive symptoms ascertained using the Beck Depression Inventory. Outcomes: Time to kidney transplant wait-listing and time to pre-emptive wait-listing. Analytic Approach: Time-to-event analysis using Cox proportional hazards regression. Results: During a median follow-up of 5.1 years, 652 (39%) participants were wait-listed, of whom 304 were preemptively wait-listed. Adjusted for demographics, comorbid conditions, estimated glomerular filtration rate slope, and cognitive function, participants with the highest scores on the Burden and Effects scales, respectively, had lower rates of wait-listing than those with the lowest scores on the Burden (wait-listing adjusted hazard ratio [aHR], 0.70; 95% CI, 0.57-0.85; P

Abstract Background Hematuria is associated with chronic kidney disease (CKD), but has rarely been examined as a risk factor for CKD progression. We explored whether individuals with hematuria had worse outcomes compared to those without hematuria in the CRIC Study. Methods Participants were a racially and ethnically diverse group of adults (21 to 74 years), with moderate CKD. Presence of hematuria (positive dipstick) from a single urine sample was the primary predictor. Outcomes included a 50% or greater reduction in eGFR from baseline, ESRD, and death, over a median follow-up of 7.3 years, analyzed using Cox Proportional Hazards models. Net reclassification indices (NRI) and C statistics were calculated to evaluate their predictive performance. Results Hematuria was observed in 1145 (29%) of a total of 3272 participants at baseline. Individuals with hematuria were more likely to be Hispanic (22% vs. 9.5%, respectively), have diabetes (56% vs. 48%), lower mean eGFR (40.2 vs. 45.3 ml/min/1.73 m2), and higher levels of urinary albumin > 1.0 g/day (36% vs. 10%). In multivariable-adjusted analysis, individuals with hematuria had a greater risk for all outcomes during the first 2 years of follow-up: Halving of eGFR or ESRD (HR Year 1: 1.68, Year 2: 1.36), ESRD (Year 1: 1.71, Year 2: 1.39) and death (Year 1:1.92, Year 2: 1.77), and these associations were attenuated, thereafter. Based on NRIs and C-statistics, no clear improvement in the ability to improve prediction of study outcomes was observed when hematuria was included in multivariable models. Conclusion In a large adult cohort with CKD, hematuria was associated with a significantly higher risk of CKD progression and death in the first 2 years of follow-up but did not improve risk prediction.

Introduction: In the general population, medication nonadherence contributes to poorer outcomes. However, little is known about medication adherence among adults with chronic kidney disease (CKD). We evaluated the association of self-reported medication adherence with CKD progression and all-cause death in patients with CKD. Methods: In this prospective observational study of 3305 adults with mild-to-moderate CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study, the baseline self-reported medication adherence was assessed by responses to 3 questions and categorized as high, medium, and low. CKD progression (50% decline in eGFR or incident end-stage renal disease) and all-cause death were measured using multivariable Cox proportional hazards. Results: Of the patients, 68% were categorized as high adherence, 17% medium adherence, and 15% low adherence. Over a median follow-up of 6 years, there were 969 CKD progression events and 675 deaths. Compared with the high-adherence group, the low-adherence group experienced increased risk for CKD progression (hazard ratio = 1.27, 95% confidence interval = 1.05, 1.54) after adjustment for sociodemographic and clinical factors, cardiovascular medications, number of medication types, and depressive symptoms. A similar association existed between low adherence and all-cause death, but did not reach standard statistical significance (hazard ratio = 1.14 95% confidence interval = 0.88, 1.47). Conclusion: Baseline self-reported low medication adherence was associated with an increased risk for CKD progression. Future work is needed to better understand the mechanisms underlying this association and to develop interventions to improve adherence. Keywords: CKD, death, medication adherence, progression

Chronic kidney disease (CKD) is associated with an increased risk of cognitive decline, but the mechanisms remain poorly defined. We sought to determine the relation between serum inflammatory markers and risk of cognitive decline among adults with CKD. Methods: We studied 757 adults aged ≥55 years with CKD participating in the Chronic Renal Insufficiency Cohort Cognitive study. We measured interleukin (IL)−1β, IL-1 receptor antagonist, IL-6, tumor necrosis factor (TNF)−α, high-sensitivity C-reactive protein (hs-CRP), and fibrinogen in baseline plasma samples. We assessed cognitive function at regular intervals in 4 domains and defined incident impairment as a follow-up score more than 1 SD poorer than the group mean. Results: The mean age of the sample was 64.3 ± 5.6 years, and the mean follow-up was 6.2 ± 2.5 years. At baseline, higher levels of each inflammatory marker were associated with poorer age-adjusted performance. In analyses adjusted for baseline cognition, demographics, comorbid conditions, and kidney function, participants in the highest tertile of hs-CRP, the highest tertile of fibrinogen, and the highest tertile of IL-1β had an increased risk of impairment in attention compared to participants in the lowest tertile of each marker. Participants in the highest versus lowest tertile of TNF-α had a lower adjusted risk of impairment in executive function. There was no association between other inflammatory markers and change in cognitive function. Discussion: Among adults with CKD, higher levels of hs-CRP, fibrinogen, and IL-1β were associated with a higher risk of impairment in attention. Higher levels of TNF-α were associated with a lower risk of impaired executive function.

Background We tested associations of cardiac biomarkers of myocardial stretch, injury, inflammation, and fibrosis with the risk of incident atrial fibrillation (AF) in a prospective study of chronic kidney disease patients. Methods and Results The study sample was 3053 participants with chronic kidney disease in the multicenter CRIC (Chronic Renal Insufficiency Cohort) study who were not identified as having AF at baseline. Cardiac biomarkers, measured at baseline, were NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide), high‐sensitivity troponin T, galectin‐3, growth differentiation factor‐15, and soluble ST‐2. Incident AF (“AF event”) was defined as a hospitalization for AF. During a median follow‐up of 8 years, 279 (9%) participants developed a new AF event. In adjusted models, higher baseline log‐transformed NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) was associated with incident AF (adjusted hazard ratio [HR] per SD higher concentration: 2.11; 95% CI, 1.75, 2.55), as was log‐high‐sensitivity troponin T (HR 1.42; 95% CI, 1.20, 1.68). These associations showed a dose–response relationship in categorical analyses. Although log‐soluble ST‐2 was associated with AF risk in continuous models (HR per SD higher concentration 1.35; 95% CI, 1.16, 1.58), this association was not consistent in categorical analyses. Log‐galectin‐3 (HR 1.05; 95% CI, 0.91, 1.22) and log‐growth differentiation factor‐15 (HR 1.16; 95% CI, 0.96, 1.40) were not significantly associated with incident AF. Conclusions We found strong associations between higher NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) and high‐sensitivity troponin T concentrations, and the risk of incident AF in a large cohort of participants with chronic kidney disease. Increased atrial myocardial stretch and myocardial cell injury may be implicated in the high burden of AF in patients with chronic kidney disease.

Introduction A recent study found lower self-reported prevalence of tobacco smoking in a peri-urban area of Lima, Peru than previously reported in urban samples. These regions encompass substantial proportions of Peru’s population – ones at greater risk of disease due to reduced healthcare access – but have been less often studied. We validate low smoking prevalence with urine cotinine and characterize chronic disease and lung function outcomes between non-, occasional, and daily smokers. Material and Methods Data are from the CRONICAS Cohort Study, a population-based longitudinal study in four low-resource Peruvian settings, which began in 2010. Of a baseline cohort of 2978 adults, we prospectively followed 2583 (87%) to determine prevalence of chronic illness. Results In a baseline sub-sample of 382 participants, median adjusted cotinine was 0.0 mcg/mg (IQR 0–0) for both self-reported non-smokers and occasional smokers compared to 172.3 mcg/mg (IQR 0–709.2) for daily smokers. Creatinine-adjusted cotinine validated daily smoking prevalence of 4.7% at a cutoff of 100 mcg/mg. Kappa statistic for daily smoking and creatinine- adjusted cotinine ≥100 mcg/mg was 0.65 (95% CI 0.47, 0.83), indicating substantial agreement. At baseline, we found 3.3% daily and 8.9% occasional smoking by self-report for the full cohort. Follow-up indicated little difference in chronic disease prevalence between groups. Daily smokers trended toward having a greater decline in FVC (−1%; 95% CI -2.9, 0.8) and FEV1 (−1.3%; 95% CI -3.2, 0.6) over 40 months when compared to non-smokers, whereas the decline in lung function for occasional smokers was similar compared to non-smokers (−0.2% FVC; 95% CI -1.5, 1.0) and (0% FEV1; 95% CI -1.3, 1.3). Conclusions Our data places Peru within a previously-described pattern of smoking found in much of Latin America, favoring occasional over daily smoking and low cigarette consumption. We determine that there are not significant differences between smoking groups concerning chronic disease outcomes. We favor distinguishing between daily and occasional smokers in order to accurately characterize these low-use populations.

BackgroundHeart failure is common in patients with chronic kidney disease. We studied risk factors for incident heart failure among 3557 participants in the CRIC (Chronic Renal Insufficiency Cohort) Study. Methods and ResultsKidney function was assessed by estimated glomerular filtration rate (eGFR) using serum creatinine, cystatin C, or both, and 24‐hour urine albumin excretion. During an average of 6.3 years of follow‐up, 452 participants developed incident heart failure. After adjustment for age, sex, race, and clinical site, hazard ratio (95% CI) for heart failure associated with 1 SD lower creatinine‐based eGFR was 1.67 (1.49, 1.89), 1 SD lower cystatin C‐based‐eGFR was 2.43 (2.10, 2.80), and 1 SD higher log‐albuminuria was 1.65 (1.53, 1.78), all P

BackgroundThe clinical implications of ankle‐brachial index (ABI) cutpoints are not well defined in patients with chronic kidney disease (CKD) despite increased prevalence of high ABI attributed to arterial stiffness. We examined the relationship of ABI with cardiovascular disease (CVD) and all‐cause mortality among CKD patients. Methods and ResultsThree thousand six hundred twenty‐seven participants without clinical peripheral artery disease (PAD) at baseline from the Chronic Renal Insufficiency Cohort Study were included. ABI was obtained per standard protocol and CVD events were confirmed by medical record adjudication. A U‐shaped association of ABI with PAD, myocardial infarction (MI), composite CVD, and all‐cause mortality was observed. Individuals with an ABI between 1.0 and