Associations between abrupt transition, dialysis-requiring AKI, and early mortality in ESKD among U.S. veterans.

BACKGROUND: Mortality is high within the first few months of starting chronic dialysis. Pre-ESKD trajectory of kidney function has been shown to be predictive of early death after dialysis initiation. We aim to better understand how two key aspects of pre-dialysis kidney function-an abrupt transition pattern and an episode of dialysis-requiring AKI (AKI-D) leading directly to ESKD-are associated with early mortality after dialysis initiation. METHODS: We extracted national data from U.S. Veterans Health Administration cross-linked with the United States Renal Data System (USRDS) to identify patients who initiated hemodialysis during 2009-2013. We defined abrupt transition as having a mean outpatient eGFR ≥ 30 ml/min/1.73m2 within 1 year prior to ESKD. AKI-D was identified using inpatient serum creatinine measurements (serum Cr increase by at least 50% from baseline) along with billing codes for inpatient receipt of dialysis for AKI within 30 days prior to the ESKD start date. We used multivariable proportional hazards models to examine the association between patterns of kidney function prior to ESKD and all-cause mortality within 90 days after ESKD. RESULTS: Twenty-two thousand eight hundred fifteen patients were identified in the final analytic cohort of Veterans who initiated hemodialysis and entered the USRDS. We defined five patterns of kidney function decline. Most (68%) patients (N = 15,484) did not have abrupt transition and did not suffer an episode of AKI-D prior to ESKD (reference group). The remaining groups had abrupt transition, AKI-D, or both. Patients who had an abrupt transition with (N = 503) or without (N = 3611) AKI-D had the highest risk of early mortality after ESKD onset after adjustment for demographics and comorbidities (adjusted HR 2.10, 95% CI 1.66-2.65 for abrupt transition with AKI-D; adjusted HR 2.10, 95% CI 1.90-2.33 for abrupt transition without AKI-D). In contrast, patients who experienced AKI-D without an abrupt transition pattern (N = 2141 had only a modestly higher risk of early death (adjusted HR 1.19, 95% CI 1.01-1.40). CONCLUSIONS: An abrupt decline in kidney function within 1 year prior to ESKD occurred in nearly 1 in 5 incident hemodialysis patients (18%) in this national cohort of Veterans and was strongly associated with higher early mortality after ESKD onset.

Improving chronic kidney disease detection and treatment in the United States: the chronic kidney disease cascade of care (C3) study protocol.

BACKGROUND: There are major gaps in the implementation of guideline-concordant care for persons with chronic kidney disease (CKD). The CKD Cascade of Care (C3) initiative seeks to improve CKD care by improving detection and treatment of CKD in primary care. METHODS: C3 is a multi-modal initiative deployed in three major academic medical centers within the Department of Veterans Affairs (VA) Health Care System: San Francisco VA, San Diego VA, and Houston VA. The main objective of the first phase of C3 described in this protocol is to establish the infrastructure for universal CKD detection among primary care patients at high-risk for CKD with a triple-marker screen comprising cystatin C, creatinine, and albuminuria. Across the three sites, a comprehensive educational intervention and the integration of primary care-based clinical champions will be employed with the goal of improving CKD detection and treatment. The San Francisco VA will also implement a practice-facilitation intervention leveraging telehealth and health informatics tools and capabilities for enhanced CKD detection. Parallel formative evaluation across the three sites will assess the feasibility and acceptability of integrating cystatin C as part of routine CKD detection in primary care practice. The effectiveness of the interventions will be assessed using a pre-post observational design for change in the proportion of patients tested annually for CKD. Secondary outcomes will assess change in the initiation of cardio-kidney protective therapies and in nephrology referrals of high-risk patients. DISCUSSION: The first phase of C3 is a multi-facility multi-modal initiative that aims to improve CKD care by implementing a triple-marker screen for enhanced CKD detection in primary care.

Heterogeneous Exposure Associations in Observational Cohort Studies: The Example of Blood Pressure in Older Adults.

Heterogeneous exposure associations (HEAs) can be defined as differences in the association of an exposure with an outcome among subgroups that differ by a set of characteristics. In this article, we intend to foster discussion of HEAs in the epidemiologic literature and present a variant of the random forest algorithm that can be used to identify HEAs. We demonstrate the use of this algorithm in the setting of the association between systolic blood pressure and death in older adults. The training set included pooled data from the baseline examination of the Cardiovascular Health Study (1989-1993), the Health, Aging, and Body Composition Study (1997-1998), and the Sacramento Area Latino Study on Aging (1998-1999). The test set included data from the National Health and Nutrition Examination Survey (1999-2002). The hazard ratios ranged from 1.25 (95% confidence interval: 1.13, 1.37) per 10-mm Hg increase in systolic blood pressure among men aged ≤67 years with diastolic blood pressure greater than 80 mm Hg to 1.00 (95% confidence interval: 0.96, 1.03) among women with creatinine concentration ≤0.7 mg/dL and a history of hypertension. HEAs have the potential to improve our understanding of disease mechanisms in diverse populations and guide the design of randomized controlled trials to control exposures in heterogeneous populations.

Results of the CARDIA study suggest that higher dietary potassium may be kidney protective.

The association between dietary sodium and potassium intake with the development of kidney disease remains unclear, particularly among younger individuals. Here, we determined whether dietary sodium and potassium intake are associated with incident chronic kidney disease (CKD) using data from 1,030 adults (age 23-35 in 1990-1991) from the Coronary Artery Risk Development In Young Adults study, based on repeated measurements of estimated glomerular filtration rate (eGFR) and urinary albumin to creatinine ratio (ACR) from 1995 through 2015. Urinary sodium and potassium excretion (mg/day), calculated from three 24-hour urine collections in 1990-1991, were averaged to measure sodium and potassium intake. Serum creatinine was used to calculate eGFR using the CKD EPI equation; spot urine albumin and creatinine were used to calculate ACR, each at five visits from 1995-1996 through 2015-2016. CKD was defined as decreased eGFR (under 60 ml/min/1.73m2) or the development of albuminuria (ACR over 30 mg/g). We used log binomial regression models adjusted for socio-demographic, behavioral, and clinical factors to determine whether sodium and potassium intake were associated with incident CKD (decreased eGFR or developed albuminuria) among those free of CKD in 1995. Dietary sodium intake was not significantly associated with incident CKD. However, every 1,000 mg/day increment of potassium intake in 1990 was significantly associated with a 29% lower risk of incident albuminuria (relative risk 0.71, 95% confidence interval 0.53, 0.95), but not eGFR. Thus, higher dietary potassium intake may protect against the development of kidney damage, particularly albuminuria.

Electronic Decision Support for Management of CKD in Primary Care: A Pragmatic Randomized Trial.

RATIONALE & OBJECTIVE: Most adults with chronic kidney disease (CKD) in the United States are cared for by primary care providers (PCPs). We evaluated the feasibility and preliminary effectiveness of an electronic clinical decision support system (eCDSS) within the electronic health record with or without pharmacist follow-up to improve the management of CKD in primary care. STUDY DESIGN: Pragmatic cluster-randomized trial. SETTING & PARTICIPANTS: 524 adults with confirmed creatinine-based estimated glomerular filtration rates of 30 to 59mL/min/1.73m2 cared for by 80 PCPs at the University of California San Francisco. Electronic health record data were used for patient identification, intervention deployment, and outcomes ascertainment. INTERVENTIONS: Each PCP's eligible patients were randomly assigned as a group into 1 of 3 treatment arms: (1) usual care; (2) eCDSS: testing of creatinine, cystatin C, and urinary albumin-creatinine ratio with individually tailored guidance for PCPs on blood pressure, potassium, and proteinuria management, cardiovascular risk reduction, and patient education; or (3) eCDSS plus pharmacist counseling (eCDSS-PLUS). OUTCOMES: The primary clinical outcome was change in blood pressure over 12 months. Secondary outcomes were PCP awareness of CKD and use of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker and statin therapy. RESULTS: All 80 eligible PCPs participated. Mean patient age was 70 years, 47% were nonwhite, and mean estimated glomerular filtration rate was 56±0.6mL/min/1.73m2. Among patients receiving eCDSS with or without pharmacist counseling (n=336), 178 (53%) completed laboratory measurements and 138 (41%) had laboratory measurements followed by a PCP visit with eCDSS deployment. eCDSS was opened by the PCP for 102 (74%) patients, with at least 1 suggested order signed for 83 of these 102 (81%). Changes in systolic blood pressure were-2.1±1.5mm Hg with usual care, -2.8±1.8mm Hg with eCDSS, and -1.1±1.1 with eCDSS-PLUS (P=0.7). PCP awareness of CKD was 16% with usual care, 26% with eCDSS, and 32% for eCDSS-PLUS (P=0.09). In as-treated analyses, PCP awareness of CKD was significantly greater with eCDSS and eCDSS-PLUS (73% and 69%) versus usual care (47%; P=0.002). LIMITATIONS: Recruitment of smaller than intended sample size and limited uptake of the testing component of the intervention. CONCLUSIONS: Although we were unable to demonstrate the effectiveness of eCDSS to lower blood pressure and uptake of the eCDSS was limited by low testing rates, eCDSS use was high when laboratory measurements were available and was associated with higher PCP awareness of CKD. FUNDING: Grants from government (National Institutes of Health) and not-for-profit (American Heart Association) entities. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT02925962.

Chronic Kidney Disease Awareness and Longitudinal Health Outcomes: Results from the REasons for Geographic And Racial Differences in Stroke Study.

BACKGROUND: The majority of people with chronic kidney disease (CKD) are unaware of their kidney disease. Assessing the clinical significance of increasing CKD awareness has critical public health and healthcare delivery implications. Whether CKD awareness among persons with CKD is associated with longitudinal health behaviors, disease management, and health outcomes is unknown. METHODS: We analyzed data from participants with CKD in the REasons for Geographic And Racial Differences in Stroke study, a national, longitudinal, population-based cohort. Our predictor was participant CKD awareness. Outcomes were (1) health behaviors (smoking avoidance, exercise, and nonsteroidal anti-inflammatory drug use); (2) CKD management indicators (angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use, statin use, systolic blood pressure, fasting blood glucose, and body mass index); (3) change in estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR); and (4) health outcomes (incident end-stage kidney disease [ESKD], coronary heart disease [CHD], stroke, and death). Logistic and linear regressions were used to examine the association of baseline CKD awareness with outcomes of interest, adjusted for CKD stage and participant demographic and clinical factors. RESULTS: Of 6,529 participants with baseline CKD, 285 (4.4%) were aware of their CKD. Among the 3,586 participants who survived until follow-up (median 9.5 years), baseline awareness was not associated with subsequent odds of health behaviors, CKD management indicators, or changes in eGFR and UACR in adjusted analyses. Baseline CKD awareness was associated with increased risk of ESKD (adjusted hazard ratio [aHR] 1.44; 95% CI 1.08-1.92) and death (aHR 1.18; 95% CI 1.00-1.39), but not with subsequent CHD or stroke, in adjusted models. CONCLUSIONS: Individuals aware of their CKD were more likely to experience ESKD and death, suggesting that CKD awareness reflects disease severity. Most persons with CKD, including those that are high-risk, remain unaware of their CKD. There was no evidence of associations between baseline CKD awareness and longitudinal health behaviors, CKD management indicators, or eGFR decline and albuminuria.

A Virtual Multidisciplinary Care Program for Management of Advanced Chronic Kidney Disease: Matched Cohort Study.

BACKGROUND: It is not well established whether a virtual multidisciplinary care program for persons with advanced chronic kidney disease (CKD) can improve their knowledge about their disease, increase their interest in home dialysis therapies, and result in more planned outpatient (versus inpatient) dialysis starts. OBJECTIVE: We aimed to evaluate the feasibility and preliminary associations of program participation with disease knowledge, home dialysis modality preference, and outpatient dialysis initiation among persons with advanced CKD in a community-based nephrology practice. METHODS: In a matched prospective cohort, we enrolled adults aged 18 to 85 years with at least two estimated glomerular filtration rates (eGFRs) of less than 30 mL/min/1.73 m2 into the Cricket Health program and compared them with controls receiving care at the same clinic, matched on age, gender, eGFR, and presence of heart failure and diabetes. The intervention included online education materials, a virtual multidisciplinary team (nurse, pharmacist, social worker, dietician), and patient mentors. Prespecified follow-up time was nine months with extended follow-up to allow adequate time to determine the dialysis start setting. CKD knowledge and dialysis modality choice were evaluated in a pre-post survey among intervention participants. RESULTS: Thirty-seven participants were matched to 61 controls by age (mean 67.2, SD 10.4 versus mean 68.8, SD 9.5), prevalence of diabetes (54%, 20/37 versus 57%, 35/61), congestive heart failure (22%, 8/37 versus 25%, 15/61), and baseline eGFR (mean 19, SD 6 versus mean 21, SD 5 mL/min/1.73 m2), respectively. At nine-month follow-up, five patients in each group started dialysis (P=.62). Among program participants, 80% (4/5) started dialysis as an outpatient compared with 20% (1/5) of controls (OR 6.28, 95% CI 0.69-57.22). In extended follow-up (median 15.7, range 11.7 to 18.1 months), 19 of 98 patients started dialysis; 80% (8/10) of the intervention group patients started dialysis in the outpatient setting versus 22% (2/9) of control patients (hazard ratio 6.89, 95% CI 1.46-32.66). Compared to before participation, patients who completed the program had higher disease knowledge levels (mean 52%, SD 29% versus mean 94%, SD 14% of questions correct on knowledge-based survey, P<.001) and were more likely to choose a home modality as their first dialysis choice (36%, 7/22 versus 68%, 15/22, P=.047) after program completion. CONCLUSIONS: The Cricket Health program can improve patient knowledge about CKD and increase interest in home dialysis modalities, and may increase the proportion of dialysis starts in the outpatient setting.

APOL1 Kidney Risk Variants and Cardiovascular Disease: An Individual Participant Data Meta-Analysis.

BACKGROUND: Two coding variants in the apo L1 gene (APOL1) are strongly associated with kidney disease in blacks. Kidney disease itself increases the risk of cardiovascular disease, but whether these variants have an independent direct effect on the risk of cardiovascular disease is unclear. Previous studies have had inconsistent results. METHODS: We conducted a two-stage individual participant data meta-analysis to assess the association of APOL1 kidney-risk variants with adjudicated cardiovascular disease events and death, independent of kidney measures. The analysis included 21,305 blacks from eight large cohorts. RESULTS: Over 8.9±5.0 years of follow-up, 2076 incident cardiovascular disease events occurred in the 16,216 participants who did not have cardiovascular disease at study enrollment. In fully-adjusted analyses, individuals possessing two APOL1 kidney-risk variants had similar risk of incident cardiovascular disease (coronary heart disease, myocardial infarction, stroke and heart failure; hazard ratio 1.11, 95% confidence interval, 0.96 to 1.28) compared to individuals with zero or one kidney-risk variant. The risk of coronary heart disease, myocardial infarction, stroke and heart failure considered individually was also comparable by APOL1 genotype. APOL1 genotype was also not associated with death. There was no difference in adjusted associations by level of kidney function, age, diabetes status, or body-mass index. CONCLUSIONS: In this large, two-stage individual participant data meta-analysis, APOL1 kidney-risk variants were not associated with incident cardiovascular disease or death independent of kidney measures.

Neighborhood Social Context and Kidney Function Over Time: The Multi-Ethnic Study of Atherosclerosis.

RATIONALE & OBJECTIVE: Although socioeconomic status has been associated with chronic kidney disease (CKD), little is known about its relationship to residential neighborhood context. STUDY DESIGN: Secondary analysis of the Multi-Ethnic Study of Atherosclerosis (MESA), a prospective cohort study designed to investigate the development and progression of subclinical cardiovascular disease. SETTING & PARTICIPANTS: 6,814 men and women who were between 45 and 84 years of age and free of cardiovascular disease were recruited between 2000 and 2002 from Baltimore, MD; Chicago, IL; Forsyth County, NC; Los Angeles, CA; New York, NY; and St. Paul, MN. EXPOSURES: A composite neighborhood problem score (calculated based on 7 participant-reported domains at study entry: adequacy of food sources, availability of parks/playground, noise, sidewalks, traffic, trash and litter, and violence) and a social cohesion score (calculated based on 5 participant-reported attributes of people in their neighborhood: close knit; get along; willing to help neighbors; trustworthy; and share values). OUTCOMES: Estimated glomerular filtration rate (eGFR; calculated using the CKD-EPI [CKD Epidemiology Collaboration] creatinine-cystatin C equation) and an indicator of eGFR decline > 30% since study entry using follow-up eGFR quantified at 4 examinations: 2000 to 2002, 2004 to 2005, 2005 to 2007, and 2010 to 2011. ANALYTICAL APPROACH: Associations between each neighborhood measure (in separate models) and eGFR decline > 30% from baseline and annualized eGFR change were estimated using Cox proportional hazards and linear mixed regression models, respectively, adjusting for potential confounders. RESULTS: While neighborhood social context differs by race/ethnicity, neither neighborhood problems nor social cohesion was independently associated with eGFR decline after adjustment for confounders. LIMITATIONS: Incomplete capture of the early stages of eGFR decline, reliance on observational data, limited variation in neighborhood measures, and the potential for residual confounding. CONCLUSIONS: Although we showed no independent association between neighborhood context and eGFR decline, it is associated with many CKD risk factors and further work is needed to clarify whether it has an independent role in CKD.

Relationship of Estimated GFR and Albuminuria to Concurrent Laboratory Abnormalities: An Individual Participant Data Meta-analysis in a Global Consortium.

RATIONALE & OBJECTIVE: Chronic kidney disease (CKD) is complicated by abnormalities that reflect disruption in filtration, tubular, and endocrine functions of the kidney. Our aim was to explore the relationship of specific laboratory result abnormalities and hypertension with the estimated glomerular filtration rate (eGFR) and albuminuria CKD staging framework. STUDY DESIGN: Cross-sectional individual participant-level analyses in a global consortium. SETTING & STUDY POPULATIONS: 17 CKD and 38 general population and high-risk cohorts. SELECTION CRITERIA FOR STUDIES: Cohorts in the CKD Prognosis Consortium with data for eGFR and albuminuria, as well as a measurement of hemoglobin, bicarbonate, phosphorus, parathyroid hormone, potassium, or calcium, or hypertension. DATA EXTRACTION: Data were obtained and analyzed between July 2015 and January 2018. ANALYTICAL APPROACH: We modeled the association of eGFR and albuminuria with hemoglobin, bicarbonate, phosphorus, parathyroid hormone, potassium, and calcium values using linear regression and with hypertension and categorical definitions of each abnormality using logistic regression. Results were pooled using random-effects meta-analyses. RESULTS: The CKD cohorts (n=254,666 participants) were 27% women and 10% black, with a mean age of 69 (SD, 12) years. The general population/high-risk cohorts (n=1,758,334) were 50% women and 2% black, with a mean age of 50 (16) years. There was a strong graded association between lower eGFR and all laboratory result abnormalities (ORs ranging from 3.27 [95% CI, 2.68-3.97] to 8.91 [95% CI, 7.22-10.99] comparing eGFRs of 15 to 29 with eGFRs of 45 to 59mL/min/1.73m2), whereas albuminuria had equivocal or weak associations with abnormalities (ORs ranging from 0.77 [95% CI, 0.60-0.99] to 1.92 [95% CI, 1.65-2.24] comparing urinary albumin-creatinine ratio > 300 vs < 30mg/g). LIMITATIONS: Variations in study era, health care delivery system, typical diet, and laboratory assays. CONCLUSIONS: Lower eGFR was strongly associated with higher odds of multiple laboratory result abnormalities. Knowledge of risk associations might help guide management in the heterogeneous group of patients with CKD.