Frailty and Cardiovascular Outcomes in Adults With CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study.

RATIONALE & OBJECTIVE: Frailty is common in individuals with chronic kidney disease (CKD) and increases the risk of adverse outcomes in adults with kidney failure requiring dialysis. However, this relationship has not been thoroughly evaluated among those with non-dialysis-dependent CKD. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 2,539 adults in the Chronic Renal Insufficiency Cohort Study. EXPOSURE: Frailty status assessed using 5 criteria: slow gait speed, muscle weakness, low physical activity, exhaustion, and unintentional weight loss. OUTCOME: Atherosclerotic events, incident heart failure, all-cause death, and cardiovascular death. ANALYTICAL APPROACH: Cause-specific hazards models. RESULTS: At study entry, the participants' mean age was 62 years, 46% were female, the mean estimated glomerular filtration rate was 45.4mL/min/1.73m2, and the median urine protein was 0.2mg/day. Frailty status was as follows: 12% frail, 51% prefrail, and 37% nonfrail. Over a median follow-up of 11.4 years, there were 393 atherosclerotic events, 413 heart failure events, 497 deaths, and 132 cardiovascular deaths. In multivariable regression analyses, compared with nonfrailty, both frailty and prefrailty status were each associated with higher risk of an atherosclerotic event (HR, 2.03 [95% CI, 1.41-2.91] and 1.77 [95% CI, 1.35-2.31], respectively) and incident heart failure (HR, 2.22 [95% CI, 1.59-3.10] and 1.39 [95% CI, 1.07-1.82], respectively), as well as higher risk of all-cause death (HR, 2.52 [95% CI, 1.84-3.45] and 1.76 [95% CI, 1.37-2.24], respectively) and cardiovascular death (HR, 3.01 [95% CI, 1.62-5.62] and 1.78 [95% 1.06-2.99], respectively). LIMITATIONS: Self-report of aspects of the frailty assessment and comorbidities, which may have led to bias in some estimates. CONCLUSIONS: In adults with CKD, frailty status was associated with higher risk of cardiovascular events and mortality. Future studies are needed to evaluate the impact of interventions to reduce frailty on cardiovascular outcomes in this population. PLAIN-LANGUAGE SUMMARY: Frailty is common in individuals with chronic kidney disease (CKD) and increases the risk of adverse outcomes. We sought to evaluate the association of frailty status with cardiovascular events and death in adults with CKD. Frailty was assessed according to the 5 phenotypic criteria detailed by Fried and colleagues. Among 2,539 participants in the CRIC Study, we found that 12% were frail, 51% were prefrail, and 37% were nonfrail. Frailty status was associated with an increased risk of atherosclerotic events, incident heart failure, and death.

Association of Proximal Tubular Secretory Clearance with Long-Term Decline in Cognitive Function.

BACKGROUND: People with chronic kidney disease (CKD) are at high risk for cognitive impairment and progressive cognitive decline. Retention of protein-bound organic solutes that are normally removed by tubular secretion is hypothesized to contribute to cognitive impairment in CKD. METHODS: We followed 2362 participants who were initially free of cognitive impairment and stroke in the prospective Chronic Renal Insufficiency Cohort (CRIC) Study. We estimated tubular secretory clearance by the 24-hour kidney clearances of eight endogenous solutes that are primarily eliminated by tubular secretion. CRIC study investigators assessed participants' cognitive function annually using the Modified Mini-Mental State (3MS) Examination. Cognitive decline was defined as a sustained decrease of more than five points in the 3MS score from baseline. Using Cox regression models adjusted for potential confounders, we analyzed associations between secretory solute clearances, serum solute concentrations, and cognitive decline. RESULTS: The median number of follow-up 3MS examinations was six per participant. There were 247 incident cognitive decline events over a median of 9.1 years of follow-up. Lower kidney clearances of five of the eight secretory solutes (cinnamoylglycine, isovalerylglycine, kynurenic acid, pyridoxic acid, and tiglylglycine) were associated with cognitive decline after adjustment for baseline eGFR, proteinuria, and other confounding variables. Effect sizes ranged from a 17% to a 34% higher risk of cognitive decline per 50% lower clearance. In contrast, serum concentrations of the solutes were not associated with cognitive decline. CONCLUSIONS: Lower kidney clearances of secreted solutes are associated with incident global cognitive decline in a prospective study of CKD, independent of eGFR. Further work is needed to determine the domains of cognition most affected by decreased secretory clearance and the mechanisms of these associations.

A Comparative Study of Serum Phosphate and Related Parameters in Chronic Kidney Disease between the USA and Japan.

INTRODUCTION: Recent studies have suggested a higher incidence of cardiovascular disease (CVD) among patients with chronic kidney disease (CKD) in the USA than in Japan. Hyperphosphatemia, a possible risk for CVD, may explain this difference; however, international differences in phosphate parameters in CKD have not been well elaborated. METHODS: By using the baseline data from the USA and the Japanese nation-wide, multicenter, CKD cohort studies; the Chronic Renal Insufficiency Cohort Study (CRIC, N = 3,870) and the Chronic Kidney Disease-Japan Cohort Study (CKD-JAC, N = 2,632), we harmonized the measures and compared clinical parameters regarding phosphate metabolism or serum phosphate, fibroblast growth factor-23 (FGF23), and parathyroid hormone (PTH), in the cross-sectional model. RESULTS: Multivariable linear regression analyses revealed that serum phosphate levels were significantly higher in CRIC across all levels of estimated glomerular filtration rate (eGFR) with the greatest difference being observed at lower levels of eGFR. Serum FGF23 and 25-hydroxy vitamin D (25OHD) levels were higher in CRIC, while PTH levels were higher in CKD-JAC at all levels of eGFR. Adjustments for demographics, 25OHD, medications, dietary intake or urinary excretion of phosphate, PTH, and FGF23 did not eliminate the difference in serum phosphate levels between the cohorts (0.43, 0.46, 0.54, 0.64, and 0.78 mg/dL higher in CRIC within eGFR strata of >50, 41-50, 31-40, 21-30, and ≤20 mL/min/1.73 m2, respectively). These findings were consistent when only Asian CRIC participants (N = 105) were included in the analysis. CONCLUSION: Serum phosphate levels in CRIC were significantly higher than those of CKD-JAC across all stages of CKD, which may shed light on the international variations in phosphate parameters and thus in cardiovascular risk among CKD patients. The key mechanisms for the substantial differences in phosphate parameters need to be elucidated.

High-Throughput Metabolomics and Diabetic Kidney Disease Progression: Evidence from the Chronic Renal Insufficiency (CRIC) Study.

INTRODUCTION: Metabolomics could offer novel prognostic biomarkers and elucidate mechanisms of diabetic kidney disease (DKD) progression. Via metabolomic analysis of urine samples from 995 CRIC participants with diabetes and state-of-the-art statistical modeling, we aimed to identify metabolites prognostic to DKD progression. METHODS: Urine samples (N = 995) were assayed for relative metabolite abundance by untargeted flow-injection mass spectrometry, and stringent statistical criteria were used to eliminate noisy compounds, resulting in 698 annotated metabolite ions. Utilizing the 698 metabolites' ion abundance along with clinical data (demographics, blood pressure, HbA1c, eGFR, and albuminuria), we developed univariate and multivariate models for the eGFR slope using penalized (lasso) and random forest models. Final models were tested on time-to-ESKD (end-stage kidney disease) via cross-validated C-statistics. We also conducted pathway enrichment analysis and a targeted analysis of a subset of metabolites. RESULTS: Six eGFR slope models selected 9-30 variables. In the adjusted ESKD model with highest C-statistic, valine (or betaine) and 3-(4-methyl-3-pentenyl)thiophene were associated (p < 0.05) with 44% and 65% higher hazard of ESKD per doubling of metabolite abundance, respectively. Also, 13 (of 15) prognostic amino acids, including valine and betaine, were confirmed in the targeted analysis. Enrichment analysis revealed pathways implicated in kidney and cardiometabolic disease. CONCLUSIONS: Using the diverse CRIC sample, a high-throughput untargeted assay, followed by targeted analysis, and rigorous statistical analysis to reduce false discovery, we identified several novel metabolites implicated in DKD progression. If replicated in independent cohorts, our findings could inform risk stratification and treatment strategies for patients with DKD.

Association Between Kidney Clearance of Secretory Solutes and Cardiovascular Events: The Chronic Renal Insufficiency Cohort (CRIC) Study.

RATIONALE & OBJECTIVE: The clearance of protein-bound solutes by the proximal tubules is an innate kidney mechanism for removing putative uremic toxins that could exert cardiovascular toxicity in humans. However, potential associations between impaired kidney clearances of secretory solutes and cardiovascular events among patients with chronic kidney disease (CKD) remains uncertain. STUDY DESIGN: A multicenter, prospective, cohort study. SETTING & PARTICIPANTS: We evaluated 3,407 participants from the Chronic Renal Insufficiency Cohort (CRIC) study. EXPOSURES: Baseline kidney clearances of 8 secretory solutes. We measured concentrations of secretory solutes in plasma and paired 24-hour urine specimens using liquid chromatography-tandem mass spectrometry (LC-MS/MS). OUTCOMES: Incident heart failure, myocardial infarction, and stroke events. ANALYTICAL APPROACH: We used Cox regression to evaluate associations of baseline secretory solute clearances with incident study outcomes adjusting for estimated GFR (eGFR) and other confounders. RESULTS: Participants had a mean age of 56 years; 45% were women; 41% were Black; and the median estimated glomerular filtration rate (eGFR) was 43 mL/min/1.73 m2. Lower 24-hour kidney clearance of secretory solutes were associated with incident heart failure and myocardial infarction but not incident stroke over long-term follow-up after controlling for demographics and traditional risk factors. However, these associations were attenuated and not statistically significant after adjustment for eGFR. LIMITATIONS: Exclusion of patients with severely reduced eGFR at baseline; measurement variability in secretory solutes clearances. CONCLUSIONS: In a national cohort study of CKD, no clinically or statistically relevant associations were observed between the kidney clearances of endogenous secretory solutes and incident heart failure, myocardial infarction, or stroke after adjustment for eGFR. These findings suggest that tubular secretory clearance provides little additional information about the development of cardiovascular disease events beyond glomerular measures of GFR and albuminuria among patients with mild-to-moderate CKD.

Differential network enrichment analysis reveals novel lipid pathways in chronic kidney disease.

MOTIVATION: Functional enrichment testing methods can reduce data comprising hundreds of altered biomolecules to smaller sets of altered biological 'concepts' that help generate testable hypotheses. This study leveraged differential network enrichment analysis methodology to identify and validate lipid subnetworks that potentially differentiate chronic kidney disease (CKD) by severity or progression. RESULTS: We built a partial correlation interaction network, identified highly connected network components, applied network-based gene-set analysis to identify differentially enriched subnetworks, and compared the subnetworks in patients with early-stage versus late-stage CKD. We identified two subnetworks 'triacylglycerols' and 'cardiolipins-phosphatidylethanolamines (CL-PE)' characterized by lower connectivity, and a higher abundance of longer polyunsaturated triacylglycerols in patients with severe CKD (stage ≥4) from the Clinical Phenotyping Resource and Biobank Core. These finding were replicated in an independent cohort, the Chronic Renal Insufficiency Cohort. Using an innovative method for elucidating biological alterations in lipid networks, we demonstrated alterations in triacylglycerols and cardiolipins-phosphatidylethanolamines that precede the clinical outcome of end-stage kidney disease by several years. AVAILABILITY AND IMPLEMENTATION: A complete list of NetGSA results in HTML format can be found at http://metscape.ncibi.org/netgsa/12345-022118/cric_cprobe/022118/results_cric_cprobe/main.html. The DNEA is freely available at https://github.com/wiggie/DNEA. Java wrapper leveraging the cytoscape.js framework is available at http://js.cytoscape.org. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Integrating a Medical Home in an Outpatient Dialysis Setting: Effects on Health-Related Quality of Life.

BACKGROUND: Integrating primary care has been proposed to reduce fragmented care delivery for patients with complex medical needs. Because of their high rates of morbidity, healthcare use, and mortality, patients with end-stage kidney disease (ESKD) may benefit from increased access to a primary care medical home. OBJECTIVE: To evaluate the effect of integrating a primary care medical home on health-related quality of life (HRQOL) for patients with ESKD receiving chronic hemodialysis. DESIGN: Before-after intervention trial with repeated measures at two Chicago dialysis centers. PARTICIPANTS: Patients receiving hemodialysis at either of the two centers. INTERVENTION: To the standard hemodialysis team (nephrologist, nurse, social worker, dietitian), we added a primary care physician, a pharmacist, a nurse coordinator, and a community health worker. The intervention took place from January 2015 through August 2016. MAIN MEASURES: Health-related quality of life, using the Kidney Disease Quality of Life (KDQOL) measures. KEY RESULTS: Of 247 eligible patients, 175 (71%) consented and participated; mean age was 54 years; 55% were men and 97% were African American or Hispanic. In regression analysis adjusted for individual visits with the medical home providers and other factors, there were significant improvements in four of five KDQOL domains: at 12 and 18 months, the Mental Component Score improved from baseline (adjusted mean 49.0) by 2.64 (p = 0.01) and 2.96 (p = 0.007) points, respectively. At 6 and 12 months, the Symptoms domain improved from baseline (adjusted mean = 77.0) by 2.61 (p = 0.02) and 2.35 points (p = 0.05) respectively. The Kidney Disease Effects domain improved from baseline (adjusted mean = 72.7), to 6, 12, and 18 months by 4.36 (p = 0.003), 6.95 (p < 0.0001), and 4.14 (p = 0.02) points respectively. The Physical Component Score improved at 6 months only. CONCLUSIONS: Integrating primary care and enhancing care coordination in two dialysis facilities was associated with improvements in HRQOL among patients with ESKD who required chronic hemodialysis.

Effects of Intensive Blood Pressure Treatment on Acute Kidney Injury Events in the Systolic Blood Pressure Intervention Trial (SPRINT).

BACKGROUND: Treating to a lower blood pressure (BP) may increase acute kidney injury (AKI) events. STUDY DESIGN: Data for AKI resulting in or during hospitalization or emergency department visits were collected as part of the serious adverse events reporting process of the Systolic Blood Pressure Intervention Trial (SPRINT). SETTING & PARTICIPANTS: 9,361 participants 50 years or older with 1 or more risk factors for cardiovascular disease. INTERVENTIONS: Participants were randomly assigned to a systolic BP target of <120 (intensive arm) or <140mmHg (standard arm). OUTCOMES & MEASUREMENTS: Primary outcome was the number of adjudicated AKI events. Secondary outcomes included severity of AKI and degree of recovery of kidney function after an AKI event. Baseline creatinine concentration was defined as the most recent SPRINT outpatient creatinine value before the date of the AKI event. RESULTS: There were 179 participants with AKI events in the intensive arm and 109 in the standard arm (3.8% vs 2.3%; HR, 1.64; 95% CI, 1.30-2.10; P<0.001). Of 288 participants with an AKI event, 248 (86.1%) had a single AKI event during the trial. Based on modified KDIGO (Kidney Disease: Improving Global Outcomes) criteria for severity of AKI, the number of AKI events in the intensive versus standard arm by KDIGO stage was 128 (58.5%) versus 81 (62.8%) for AKI stage 1, 42 (19.2%) versus 18 (14.0%) for AKI stage 2, and 42 (19.2%) versus 25 (19.4%) for AKI stage 3 (P=0.5). For participants with sufficient data, complete or partial resolution of AKI was seen for 169 (90.4%) and 9 (4.8%) of 187 AKI events in the intensive arm and 86 (86.9%) and 4 (4.0%) of 99 AKI events in the standard arm, respectively. LIMITATIONS: Trial results are not generalizable to patients with diabetes mellitus or without risk factors for cardiovascular disease. CONCLUSIONS: More intensive BP lowering resulted in more frequent episodes of AKI. Most cases were mild and most participants had complete recovery of kidney function. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT01206062.

Risks of Adverse Events in Advanced CKD: The Chronic Renal Insufficiency Cohort (CRIC) Study.

BACKGROUND: People with advanced chronic kidney disease are at risk for the development of end-stage renal disease (ESRD), but also many other adverse outcomes, including cardiovascular disease (CVD) events and death. Determination of risk factors that explain the variability in prognosis and timing of these adverse outcomes can aid patient counseling and medical decision making. STUDY DESIGN: Prospective research cohort. SETTING & PARTICIPANTS: 1,798 participants with estimated glomerular filtration rates (eGFRs)<30mL/min/1.73m2 in the CRIC Study were followed up for a median of 5.5 years. PREDICTORS: Age, race, sex, eGFR, proteinuria, diabetes mellitus, body mass index, ejection fraction, systolic blood pressure, history of CVD, and smoking history. OUTCOMES: ESRD, CVD (congestive heart failure, stroke, myocardial infarction, and peripheral artery disease), and death. RESULTS: Baseline age of the cohort was 60 years, 46% were women, and 46% were African American. Although 52.3% of participants progressed to ESRD during follow-up, the path by which this occurred was variable. For example, predicted 1-year probabilities for a hypothetical 60-year-old white woman with eGFR of 30mL/min/1.73m2, urine protein excretion of 1.8g/d, and no diabetes or CVD (risk characteristics similar to the average participant) were 3.3%, 4.1%, and 0.3%, for first developing CVD, ESRD, and death, respectively. For a 40-year-old African American man with similar characteristics but higher systolic blood pressure, the corresponding 1-year probabilities were 2.4%, 13.2%, and 0.1%. For all participants, the development of ESRD or CVD increased the risk for subsequent mortality, with no differences by patient race or body mass index. LIMITATIONS: The CRIC population was specifically recruited for kidney disease, and the vast majority had seen a nephrologist. CONCLUSIONS: The prognosis and timing of adverse outcomes in chronic kidney disease vary by patient characteristics. These results may help guide the development of personalized approaches for managing patients with advanced CKD.

Healthy lifestyle and risk of kidney disease progression, atherosclerotic events, and death in CKD: findings from the Chronic Renal Insufficiency Cohort (CRIC) Study.

BACKGROUND: In general populations, healthy lifestyle is associated with fewer adverse outcomes. We estimated the degree to which adherence to a healthy lifestyle decreases the risk of renal and cardiovascular events among adults with chronic kidney disease (CKD). STUDY DESIGN: Prospective cohort. SETTING & PARTICIPANTS: 3,006 adults enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study. PREDICTORS: 4 lifestyle factors (regular physical activity, body mass index [BMI] of 20-<25kg/m(2), nonsmoking, and "healthy diet"), individually and in combination. OUTCOMES: CKD progression (50% decrease in estimated glomerular filtration rate or end-stage renal disease), atherosclerotic events (myocardial infarction, stroke, or peripheral arterial disease), and all-cause mortality. MEASUREMENTS: Multivariable-adjusted Cox proportional hazards. RESULTS: During a median follow-up of 4 years, we observed 726 CKD progression events, 355 atherosclerotic events, and 437 deaths. BMI≥25kg/m(2) and nonsmoking were associated with reduced risk of CKD progression (HRs of 0.75 [95% CI, 0.58-0.97] and 0.61 [95% CI, 0.45-0.82] for BMIs of 25 to <30 and ≥30kg/m(2), respectively, versus 20 to <25kg/m(2); HR for nonsmoking of 0.68 [95% CI, 0.55-0.84] compared to the current smoker reference group) and reduced risk of atherosclerotic events (HRs of 0.67 [95% CI, 0.46-0.96] for BMI of 25-<30 vs 20-<25kg/m(2) and 0.55 [95% CI, 0.40-0.75] vs current smoker). Factors associated with reduced all-cause mortality were regular physical activity (HR, 0.64 [95% CI, 0.52-0.79] vs inactive), BMI≥30kg/m(2) (HR, 0.64 [95% CI, 0.43-0.96] vs 20-<25kg/m(2)), and nonsmoking (HR, 0.45 [95% CI, 0.34-0.60] vs current smoker). BMI<20kg/m(2) was associated with increased all-cause mortality risk (HR, 2.11 [95% CI, 1.13-3.93] vs 20-<25kg/m(2)). Adherence to all 4 lifestyle factors was associated with a 68% lower risk of all-cause mortality compared to adherence to no lifestyle factors (HR, 0.32; 95% CI, 0.11-0.89). LIMITATIONS: Lifestyle factors were measured only once. CONCLUSIONS: Regular physical activity, nonsmoking, and BMI≥25kg/m(2) were associated with lower risk of adverse outcomes in this cohort of individuals with CKD.

Plant protein intake is associated with fibroblast growth factor 23 and serum bicarbonate levels in patients with chronic kidney disease: the Chronic Renal Insufficiency Cohort study.

BACKGROUND: Protein from plant, as opposed to animal, sources may be preferred in chronic kidney disease (CKD) because of the lower bioavailability of phosphate and lower nonvolatile acid load. STUDY DESIGN: Observational cross-sectional study. SETTING AND PARTICIPANTS: A total of 2,938 participants with CKD and information on their dietary intake at the baseline visit in the Chronic Renal Insufficiency Cohort Study. PREDICTORS: Percentage of total protein intake from plant sources (percent plant protein) was determined by scoring individual food items using the National Cancer Institute Diet History Questionnaire (DHQ). OUTCOMES: Metabolic parameters, including serum phosphate, bicarbonate (HCO3), potassium, and albumin, plasma fibroblast growth factor 23 (FGF-23), and parathyroid hormone (PTH), and hemoglobin levels. MEASUREMENTS: We modeled the association between percent plant protein and metabolic parameters using linear regression. Models were adjusted for age, sex, race, diabetes status, body mass index, estimated glomerular filtration rate, income, smoking status, total energy intake, total protein intake, 24-hour urinary sodium concentration, use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and use of diuretics. RESULTS: Higher percent plant protein was associated with lower FGF-23 (P = .05) and higher HCO3 (P = .01) levels, but not with serum phosphate or parathyroid hormone concentrations (P = .9 and P = .5, respectively). Higher percent plant protein was not associated with higher serum potassium (P = .2), lower serum albumin (P = .2), or lower hemoglobin (P = .3) levels. The associations of percent plant protein with FGF-23 and HCO3 levels did not differ by diabetes status, sex, race, CKD stage (2/3 vs. 4/5), or total protein intake (≤0.8 g/kg/day vs. >0.8 g/kg/day; P-interaction >.10 for each). LIMITATIONS: This is a cross-sectional study; determination of percent plant protein using the Diet History Questionnaire has not been validated. CONCLUSIONS: Consumption of a higher percentage of protein from plant sources may lower FGF-23 and raise HCO3 levels in patients with CKD.

Social Support in Older Adults With CKD: A Report From the CRIC (Chronic Renal Insufficiency Cohort) Study.

RATIONALE & OBJECTIVE: Social support in older adults with chronic kidney disease (CKD) is a potentially modifiable factor that may affect important clinical outcomes such as health-related quality of life, cognitive function, and frailty. However, limited data about the effects of social support in older patients with non-dialysis-dependent CKD exist. Our objective was to evaluate the association of social support with health-related quality of life, cognitive function, and frailty in older adults with CKD. STUDY DESIGN: Cross-sectional analysis of a prospective cohort study. SETTING & POPULATION: 1,851 participants older than 65 years with CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study. EXPOSURE: Social support (Lubben Social Network Scale [LSNS]). OUTCOMESS: Health-related quality of life (Kidney Disease Quality of Life-36), cognitive function (Modified Mini-Mental State Examination, Trail Making Test A & B, and Buschke Selective Reminder Tests), and frailty (modified Fried frailty criteria). ANALYTIC APPROACH: Multivariable, linear, and logistic regression to determine the association between social support and health-related quality of life, cognitive function, and frailty. RESULTS: Low social support, defined as LSNS score < 12, was present in 22% of participants. On multivariable analysis, higher social support was associated with higher health-related quality of life (ß coefficient per 1-SD increase in LSNS score; burden subscale, 2.57 (95% CI, 1.57-3.56); effects subscale, 2.21 (95% CI, 1.52-2.9); symptoms subscale, 1.64 (95% CI, 0.88-2.41); mental health composite subscale, 1.91 (95% CI, 1.40-2.43); and physical health composite score, 0.64 (95% CI, 0.03-1.24)). Higher social support was associated with better cognitive function (ß coefficient per 1-SD increase in LSNS score; Modified Mini-Mental State Examination, 0.81 (95% CI, 0.44 to 1.19); Trail Making Test A & B, -2.53 (95% CI, -4.29 to -0.76) and -6.53 (95% CI, -10.07 to -2.99), respectively; Buschke Selective Reminder Test 1, 2, and 3, 0.19 (95% CI, 0.07 to 0.30); 1.59 (95% CI, 0.96 to 2.22); and 0.40 (95% CI, 0.23 to 0.56), respectively. Higher social support was associated with higher likelihood of being nonfrail (OR, 1.77; 95% CI per 1-SD higher LSNS score, 1.24-2.53). LIMITATIONS: Conclusions about causality cannot be drawn from an observational cross-sectional study. CONCLUSIONS: In older patients with CKD, higher social support was associated with higher health-related quality of life and cognitive function and less frailty.

Health-Related Quality of Life, Depressive Symptoms, and Kidney Transplant Access in Advanced CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study.

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 < 0.001) and Effects scales (wait-listing aHR, 0.74; 95% CI, 0.59-0.92; P = 0.007). Participants with fewer depressive symptoms (ie, Beck Depression Inventory score < 14) had lower wait-listing rates than those with more depressive symptoms (aHR, 0.81; 95% CI, 0.66-0.99; P = 0.04). Participants with lower Burden and Effects scale scores and those with higher Symptoms and PCS scores had higher pre-emptive wait-listing rates (aHR in highest tertile of PCS relative to lowest tertile, 1.58; 95% CI, 1.12-2.23; P = 0.01). LIMITATIONS: Unmeasured confounders. CONCLUSIONS: Self-reported health in late-stage CKD may influence the timing of kidney transplantation.

Research-based versus clinical serum creatinine measurements and the association of acute kidney injury with subsequent kidney function: findings from the Chronic Renal Insufficiency Cohort study.

BACKGROUND: Observational studies relying on clinically obtained data have shown that acute kidney injury (AKI) is linked to accelerated chronic kidney disease (CKD) progression. However, prior reports lacked uniform collection of important confounders such as proteinuria and pre-AKI kidney function trajectory, and may be susceptible to ascertainment bias, as patients may be more likely to undergo kidney function testing after AKI. METHODS: We studied 444 adults with CKD who participated in the prospective Chronic Renal Insufficiency Cohort (CRIC) Study and were concurrent members of a large integrated healthcare delivery system. We estimated glomerular filtration rate (eGFR) trajectories using serum creatinine measurements from (i) the CRIC research protocol (yearly) and (ii) routine clinical care. We used linear mixed effects models to evaluate the associations of AKI with acute absolute change in eGFR and post-AKI eGFR slope, and explored whether these varied by source of creatinine results. Models were adjusted for demographic characteristics, diabetes status and albuminuria. RESULTS: During median follow-up of 8.5 years, mean rate of eGFR loss was -0.31 mL/min/1.73 m2/year overall, and 73 individuals experienced AKI (55% Stage 1). A significant interaction existed between AKI and source of serum creatinine for acute absolute change in eGFR level after discharge; in contrast, AKI was independently associated with a faster rate of eGFR decline (mean additional loss of -0.67 mL/min/1.73 m2/year), which was not impacted by source of serum creatinine. CONCLUSIONS: AKI is independently associated with subsequent steeper eGFR decline regardless of the serum creatinine source used, but the strength of association is smaller than observed in prior studies after taking into account key confounders such as pre-AKI eGFR slope and albuminuria.

Facilitating primary care provider use in a patient-centered medical home intervention study for chronic hemodialysis patients.

Patients with chronic kidney disease have a high disease burand may benefit from primary care services and care coord A medical home model with direct access to primary care services is one approach that may address this need, yet has not been examined. As a substudy of the Patient-Centered Outcomes Research Institute (PCORI) patient-centered medical home for kidney disease (PCMH-KD) health system intervention study, we examined the uptake of free primary care physician (PCP) services. The PCORI PCMH-KD study was an initial step toward integrating PCPs, a nurse coordinator, a pharmacist, and community health workers (CHWs) within the health care delivery team. Adult chronic hemodialysis (CHD) at two urban dialysis centers were enrolled in the intervention. We examined trends and factors associated with the use of the PCMH-KD PCP among two groups of patients based on their report of having a regular physician for at least six months (established-PCP) or not (no-PCP). Of the 173 enrolled patients, 91 (53%) patients had at least one visit with the PCMH-KD PCP. The rate of visits was higher in those in the no-PCP group compared with those in the established-PCP group (62% vs. 41%, respectively). Having more visits with the CHW was positively associated with having a visit with the PCMH-KD PCPs for both groups. Embedded CHWs within the care team played a role in facilithe uptake of PCMH-KD PCP. Lessons from this health system intervention can inform future approaches on the integration of PCPs and care coordination for CHD patients.

Self-reported Medication Adherence and CKD Progression.

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.