Association of Race With Mortality and Cardiovascular Events in a Large Cohort of US Veterans

Abrupt Decline in Kidney Function Precipitating Initiation of Chronic Renal Replacement Therapy

INTRODUCTION

Abrupt declines in kidney function often occur in patients with advanced chronic kidney disease and may exacerbate the need to initiate dialysis treatment. It is unclear how frequently such events occur in patients transitioning to chronic dialysis therapy, and what outcomes they are associated with.

METHODS

We examined a national cohort of 23,349 US veterans with incident end-stage renal disease (ESRD) and with available pre-ESRD estimated glomerular filtration rate (eGFR) to identify abrupt declines in kidney function, defined as an unexpected >50% decrease in eGFR at the time of chronic dialysis transition. Associations with all-cause mortality and with renal recovery were examined in Cox proportional hazard and competing risk regression models.

RESULTS

A total of 4804 (21%) patients experienced an abrupt decline in kidney function at dialysis transition. Renal recovery occurred in 586 (12.2%) and 297 (1.6%) patients with and without an abrupt decline, respectively (adjusted subhazard ratio: 4.42; 95% confidence interval [CI]: 3.72-5.27; P < 0.001). In the first 6 months after dialysis transition 1178 patients (24.5%) with abrupt decline died (annualized mortality rate 574/1000 patient-years), compared with 2354 deaths (12.7%) in patients without abrupt decline (274 deaths/1000 patient-years). An abrupt decline was associated with 45% higher mortality after multivariable adjustments (hazard ratio: 1.45; 95% CI: 1.33-1.57).

CONCLUSION

Abrupt declines in kidney function are common in patients transitioning to chronic dialysis, and are associated with higher mortality. Patients with abrupt declines also experience a higher rate of renal recovery; hence, careful attention to residual kidney function is warranted in these patients.

Delivering a "New Deal" of Kidney Health Opportunities to Improve Outcomes Within the Veterans Health Administration

Just as the "New Deal" aimed to elevate the "forgotten man" of the Great Depression through governmental relief and reform, so does the Department of Veterans Affairs (VA) health care system aim to improve the health of veterans with the invisible illness of chronic kidney disease through a concerted series of health care delivery reforms. Augmenting its primary care platform with advances in informatics and health service delivery initiatives targeting kidney disease, the VA is changing how nephrology care is provided to veterans with the goal of optimized population kidney health. As the largest provider of kidney health services in the country, the VA offers an instructive case study of the value of comprehensive health care coverage for people with chronic kidney disease. Recent reports of kidney health outcomes among veterans support the benefit of the VA's integrated health care delivery system. Suggestions to optimize veterans' kidney health further may be equally applicable to other health systems caring for people afflicted with kidney disease.

Pre-end-stage renal disease visit-to-visit systolic blood pressure variability and post-end-stage renal disease mortality in incident dialysis patients

OBJECTIVES

Higher SBP visit-to-visit variability (SBPV) has been associated with increased risk of adverse events in patients with chronic kidney disease, but the association of SBPV in advanced nondialysis-dependent chronic kidney disease with mortality after the transition to end-stage renal disease (ESRD) remains unknown.

METHODS

Among 17 729 US veterans transitioning to dialysis between October 2007 and September 2011, we assessed SBPV calculated from the SD of at least three intraindividual outpatient SBP values during the last year prior to dialysis transition (prelude period). Outcomes included factors associated with higher prelude SBPV and post-transition all-cause, cardiovascular, and infection-related mortality, assessed using multivariable linear regression and Cox and competing risk regressions, respectively, adjusted for demographics, comorbidities, medications, cardiovascular medication adherence, SBP, BMI, estimated glomerular filtration rate, and type of vascular access.

RESULTS

Modifiable clinical factors associated with higher prelude SBPV included higher SBP, use of antihypertensive medications and erythropoiesis-stimulating agents, inadequate cardiovascular medication adherence, and catheter use. After multivariable adjustment, higher prelude SBPV was significantly associated with higher post-ESRD all-cause and infection-related mortality, but not cardiovascular mortality [hazard/subhazard ratios (95% confidence interval) for the highest (vs. lowest) quartile of SBPV, 1.08 (1.01-1.16), 1.02 (0.89-1.15), and 1.41 (1.10-1.80) for all-cause, cardiovascular, and infection-related mortality, respectively].

CONCLUSION

High pre-ESRD SBPV is potentially modifiable and associated with higher all-cause and infection-related mortality following dialysis initiation. Further studies are needed to test whether modification of pre-ESRD SBPV can improve clinical outcomes in incident ESRD patients. VIDEO ABSTRACT:.

Treatment of rheumatoid arthritis with biologic agents lowers the risk of incident chronic kidney disease

Rheumatoid arthritis is associated with reduced kidney function, possibly due to chronic inflammation or the use of nephrotoxic therapies. However, little is known about the effects of using the newer novel non-nephrotoxic biologic agents on the risk of incident chronic kidney disease (CKD). To study this we used a cohort of 20,757 United States veterans diagnosed with rheumatoid arthritis with an estimated glomerular filtration rate (eGFR) of 60 mL/min/1.73m² or more, recruited between October 2004 and September 2006, and followed through 2013. The associations of biologic use with incident CKD (eGFR under 60 with a decrease of at least 25% from baseline, and eGFR under 45 mL/min/1.73m²) and change in eGFR (<-3, -3 to <0 [reference], and ≥0 mL/min/1.73m²/year) were examined in propensity-matched patients based on their likelihood to initiate biologic treatment, using Cox models and multinomial logistic regression models, respectively. Among 20,757 patients, 4,617 started biologic therapy. In the propensity-matched cohort, patients treated (versus not treated) with biologic agents had a lower risk of incident CKD (hazard ratios 0.95, 95% confidence interval [0.82-1.10] and 0.71 [0.53-0.94] for decrease in eGFR under 60 and under 45 mL/min/1.73m², respectively) and progressive eGFR decline (multinomial odds ratios [95% CI] for eGFR slopes <-3 and ≥0 [versus -3 to <0] mL/min/1.73m²/year, 0.67 [0.58-0.79] and 0.76 [0.69-0.83], respectively). A significant deceleration of eGFR decline was also observed after biologic administration in patients treated with biologics (-1.0 versus -0.4 [mL/min/1.73m²/year] before and after biologic use). Thus, biologic agent administration was independently associated with lower risk of incident CKD and progressive eGFR decline.

Association between vascular access creation and deceleration of estimated glomerular filtration rate decline in late-stage chronic kidney disease patients transitioning to end-stage renal disease

Background

Prior studies have suggested that arteriovenous fistula (AVF) or graft (AVG) creation may be associated with slowing of estimated glomerular filtration rate (eGFR) decline. It is unclear if this is attributable to the physiological benefits of a mature access on systemic circulation versus confounding factors.

Methods

We examined a nationwide cohort of 3026 US veterans with advanced chronic kidney disease (CKD) transitioning to dialysis between 2007 and 2011 who had a pre-dialysis AVF/AVG and had at least three outpatient eGFR measurements both before and after AVF/AVG creation. Slopes of eGFR were estimated using mixed-effects models adjusted for fixed and time-dependent confounders, and compared separately for the pre- and post-AVF/AVG period overall and in patients stratified by AVF/AVG maturation. In all, 3514 patients without AVF/AVG who started dialysis with a catheter served as comparators, using an arbitrary 6-month index date before dialysis initiation to assess change in eGFR slopes.

Results

Of the 3026 patients with AVF/AVG (mean age 67 years, 98% male, 75% diabetic), 71% had a mature AVF/AVG at dialysis initiation. eGFR decline accelerated in the last 6 months prior to dialysis in patients with a catheter (median, from -6.0 to -16.3 mL/min/1.73 m2/year, P < 0.001), while a significant deceleration of eGFR decline was seen after vascular access creation in those with AVF/AVG (median, from -5.6 to -4.1 mL/min/1.73 m2/year, P < 0.001). Findings were independent of AVF/AVG maturation status and were robust in adjusted models.

Conclusions

The creation of pre-dialysis AVF/AVG appears to be associated with eGFR slope deceleration and, consequently, may delay the onset of dialysis initiation in advanced CKD patients.

Mortality Disparities in Racial/Ethnic Minority Groups in the Veterans Health Administration: An Evidence Review and Map

BACKGROUND

Continued racial/ethnic health disparities were recently described as "the most serious and shameful health care issue of our time." Although the 2014 US Affordable Care Act-mandated national insurance coverage expansion has led to significant improvements in health care coverage and access, its effects on life expectancy are not yet known. The Veterans Health Administration (VHA), the largest US integrated health care system, has a sustained commitment to health equity that addresses all 3 stages of health disparities research: detection, understanding determinants, and reduction or elimination. Despite this, racial disparities still exist in the VHA across a wide range of clinical areas and service types.

OBJECTIVES

To inform the health equity research agenda, we synthesized evidence on racial/ethnic mortality disparities in the VHA.

SEARCH METHODS

Our research librarian searched MEDLINE and Cochrane Central Registry of Controlled Trials from October 2006 through February 2017 using terms for racial groups and disparities.

SELECTION CRITERIA

We included studies if they compared mortality between any racial/ethnic minority and nonminority veteran groups or between different minority groups in the VHA (PROSPERO# CRD42015015974). We made study selection decisions on the basis of prespecified eligibility criteria. They were first made by 1 reviewer and checked by a second and disagreements were resolved by consensus (sequential review).

DATA COLLECTION AND ANALYSIS

Two reviewers sequentially abstracted data on prespecified population, outcome, setting, and study design characteristics. Two reviewers sequentially graded the strength of evidence using prespecified criteria on the basis of 5 key domains: study limitations (study design and internal validity), consistency, directness, precision of the evidence, and reporting biases. We synthesized the evidence qualitatively by grouping studies first by racial/ethnic minority group and then by clinical area. For areas with multiple studies in the same population and outcome, we pooled their reported hazard ratios (HRs) using random effects models (StatsDirect version 2.8.0; StatsDirect Ltd., Altrincham, England). We created an evidence map using a bubble plot format to represent the evidence base in 5 dimensions: odds ratio or HR of mortality for racial/ethnic minority group versus Whites, clinical area, strength of evidence, statistical significance, and racial group.

MAIN RESULTS

From 2840 citations, we included 25 studies. Studies were large (n ≥ 10 000) and involved nationally representative cohorts, and the majority were of fair quality. Most studies compared mortality between Black and White veterans and found similar or lower mortality for Black veterans. However, we found modest mortality disparities (HR or OR = 1.07, 1.52) for Black veterans with stage 4 chronic kidney disease, colon cancer, diabetes, HIV, rectal cancer, or stroke; for American Indian and Alaska Native veterans undergoing noncardiac major surgery; and for Hispanic veterans with HIV or traumatic brain injury (most low strength).

AUTHOR'S CONCLUSIONS

Although the VHA's equal access health care system has reduced many racial/ethnic mortality disparities present in the private sector, our review identified mortality disparities that have persisted mainly for Black veterans in several clinical areas. However, because most mortality disparities were supported by single studies with imprecise findings, we could not draw strong conclusions about this evidence. More disparities research is needed for American Indian and Alaska Native, Asian, and Hispanic veterans overall and for more of the largest life expectancy gaps. Public Health Implications. Because of the relatively high prevalence of diabetes in Black veterans, further research to better understand and reduce this mortality disparity may be prioritized as having the greatest potential impact. However, other mortality disparities affect thousands of veterans and cannot be ignored.

History of psychosis and mania, and outcomes after kidney transplantation - a retrospective study

History of psychosis or mania, if uncontrolled, both represent relative contraindications for kidney transplantation. We examined 3680 US veterans who underwent kidney transplantation. The diagnosis of history of psychosis/mania was based on a validated algorithm. Measured confounders were used to create a propensity score-matched cohort (n = 442). Associations between pretransplantation psychosis/mania and death with functioning graft, all-cause death, graft loss, and rejection were examined in survival models and logistic regression models. Post-transplant medication nonadherence was assessed using proportion of days covered (PDC) for tacrolimus and mycophenolic acid in both groups. The mean ± SD age of the cohort at baseline was 61 ± 11 years, 92% were male, and 66% and 27% of patients were white and African-American, respectively. Compared to patients without history of psychosis/mania, patients with a history of psychosis/mania had similar risk of death with functioning graft [subhazard ratio (SHR) (95% confidence interval (CI)): 0.94(0.42-2.09)], all-cause death [hazard ratio (95% CI): 1.04 (0.51-2.14)], graft loss [SHR (95% CI): 1.07 (0.45-2.57)], and rejection [odds ratio(95% CI): 1.23(0.60-2.53)]. Moreover, there was no difference in immunosuppressive drug PDC in patients with and without history of psychosis/mania (PDC: 76 ± 21% vs. 78 ± 19%, P = 0.529 for tacrolimus; PDC: 78 ± 17% vs. 79 ± 18%, P = 0.666 for mycophenolic acid). After careful selection, pretransplantation psychosis/mania is not associated with adverse outcomes in kidney transplant recipients.

Lack of Evidence for Racial Disparity in 30-Day All-Cause Readmission Rate for Older US Veterans Hospitalized with Heart Failure

BACKGROUND

Heart failure is the leading cause for 30-day all-cause readmission. Although racial disparities in health care are well documented, their impact on 30-day all-cause readmission rate is inconclusive.

OBJECTIVE

We examined the impact of racial disparity on 30-day readmission for hospitalized patients with heart failure.

METHODS

This is a retrospective secondary data analysis for a large veteran cohort in 130 Veterans Affairs Medical Centers. Propensity scores were used to reduce differences in age, gender, survival days, and comorbidities in index hospitalization among 46 524 whites and 14 124 African Americans (AA).

RESULTS

At index hospitalization, AA patients were younger (73.04 vs 67.10 years, t = -54.58, P < .000) and less likely to have myocardial infarcts (8.02% vs 9.80%, t = -6.36, P = .000), peripheral vascular disease (15.25% vs 22.51%, t = -18.68, P = .000), chronic obstructive pulmonary disease (39.59% vs 50.05%, t = -21.89, P < .000), and complicated diabetes (23.42% vs 26.24%, t = -6.73, P = .000). AA patients had lower mortality 30 days post-index hospitalization (3.51% vs 5.69%, t = -10.23, P = .000). In contrast, AA patients were more likely to have renal disease (44.03% vs 38.71%, t = 11.32, P < .000) and HIV/AIDS (1.56% vs 0.20%, t = 19.71, P < .000). The 30-day all-cause readmission rate before adjustments was 17.82% for AA patients versus 18.72% for white patients. There was no difference in the 2 rates after adjustments (18% vs 18%; odds of readmission = 1.002, z = 0.08, P = .937).

CONCLUSIONS

In a large Department of Veterans Affairs (VA) cohort, white and AA veterans hospitalized for heart failure had similar 30-day all-cause readmission rates after adjustments were made for age, gender, survival days, and comorbidities. However, the 30-day all-cause mortality rate was higher for white patients than for AA patients. Future prospective studies are needed to validate results and test generalizability outside the VA system of care.

Race and Socioeconomic Status Independently Affect Risk of Major Amputation in Peripheral Artery Disease

Background

Black race has been shown to be a risk factor for amputation in peripheral artery disease (PAD); however, race has been argued to be a marker for socioeconomic status (SES) rather than true disparity. The aim of this study is to study the impact of race and SES on amputation risk in PAD patients.

Methods and Results

Patients with incident PAD in the national Veterans Affairs Corporate Data Warehouse were identified from 2003 to 2014 (N=155 647). The exposures were race and SES (measured by median income in residential ZIP codes). The outcome was incident major amputation. Black veterans were significantly more likely to live in low‐SES neighborhoods and to present with advanced PAD. Black patients had a higher amputation risk in each SES stratum compared with white patients. In Cox models (adjusting for covariates), black race was associated with a 37% higher amputation risk compared with white race (hazard ratio: 1.37; 95% confidence interval, 1.30–1.45), whereas low SES was independently predictive of increased risk of amputation (hazard ratio: 1.12; 95% confidence interval, 1.06–1.17) and showed no evidence of interaction with race. In predicted amputation risk analysis, black race and low SES continued to be significant risk factors for amputation regardless of PAD presentation.

Conclusions

Black race significantly increases the risk of amputation within the same SES stratum compared with white race and has an independent effect on limb loss after controlling for comorbidities, severity of PAD at presentation, and use of medications.

FGF23 Concentration and APOL1 Genotype Are Novel Predictors of Mortality in African Americans With Type 2 Diabetes

OBJECTIVE

Cardiovascular and renal complications contribute to higher mortality in patients with diabetes. We assessed novel and conventional predictors of mortality in African American-Diabetes Heart Study (AA-DHS) participants.

RESEARCH DESIGN AND METHODS

Associations between mortality and subclinical atherosclerosis, urine albumin-to-creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), plasma fibroblast growth factor 23 (FGF23) concentration, African ancestry proportion, and apolipoprotein L1 genotypes (APOL1) were assessed in 513 African Americans with type 2 diabetes; analyses were performed using Cox proportional hazards models.

RESULTS

At baseline, participants were 55.6% female with median (25th, 75th percentile) age 55 years (49.0, 62.0), diabetes duration 8 years (5.0, 13.0), glycosylated hemoglobin 60.7 mmol/mol (48.6, 76.0), eGFR 91.3 mL/min/1.73 m² (76.4, 111.3), UACR 12.5 mg/mmol (4.2, 51.2), and coronary artery calcium 28.5 mg Ca²⁺ (1.0, 348.6); 11.5% had two APOL1 renal-risk variants. After 6.6-year follow-up (5.8, 7.5), 54 deaths were recorded. Higher levels of coronary artery calcified plaque, carotid artery calcified plaque, albuminuria, and FGF23 were associated with higher mortality after adjustment for age, sex, and African ancestry proportion. A penalized Cox regression that included all covariates and predictors associated with mortality identified male sex (hazard ratio [HR] 4.17 [95% CI 1.96-9.09]), higher FGF23 (HR 2.10 [95% CI 1.59-2.78]), and absence of APOL1 renal-risk genotypes (HR 0.07 [95% CI 0.01-0.69]) as the strongest predictors of mortality.

CONCLUSIONS

Accounting for conventional risk factors, higher FGF23 concentrations and APOL1 non-renal-risk genotypes associated with higher mortality in African Americans with diabetes. These data add to growing evidence supporting FGF23 association with mortality; mechanisms whereby these novel predictors impact survival remain to be determined.

Radical versus partial nephrectomy, chronic kidney disease progression and mortality in US veterans

Background

Partial nephrectomy is considered the preferred care for localized kidney tumors and may yield better patient and kidney survival and similar oncological outcomes compared with radical nephrectomy. We sought to reexamine these hypotheses in a large nationally representative cohort of US veterans who underwent radical or partial nephrectomy.

Methods

We identified 7073 US veterans who had a partial or radical nephrectomy between 2004 and 2013. We collected data on estimated glomerular filtration rate (eGFR) prior to admission for nephrectomy surgery, immediately after surgery and 180 days postsurgery. We evaluated the association of nephrectomy type and eGFR at different time points with long-term mortality risk in adjusted survival models.

Results

Patients who underwent radical (compared to partial) nephrectomy had a 2-fold greater decline in eGFR (-21.8 ± 17.7 versus -10.3 ± 17.4 mL/min/1.73 m2) immediately after surgery. This larger drop in eGFR resulted in a larger proportion of radical nephrectomy patients having an eGFR <60 mL/min/1.73 m2 at ≥180 days postsurgery. Radical (compared to partial) nephrectomy patients also exhibited a 2.2-fold higher mortality [adjusted death hazard ratio 2.21 (95% confidence interval 1.91-2.55)]. Low eGFRs prior to surgery and 180 days postsurgery were associated with higher risk of postnephrectomy death.

Conclusions

Worse postnephrectomy kidney function and higher mortality were observed with radical nephrectomy, and a low presurgical eGFR and a greater decrease in eGFR postsurgery were associated with worse mortality irrespective of the type of nephrectomy. Additional studies are needed to examine predictors of postnephrectomy outcomes.

Changes in Albuminuria and Subsequent Risk of Incident Kidney Disease

BACKGROUND AND OBJECTIVES

Albuminuria is a robust predictor of CKD progression. However, little is known about the associations of changes in albuminuria with the risk of kidney events outside the settings of clinical trials.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a nationwide cohort of 56,946 United States veterans with an eGFR≥60 ml/min per 1.73 m2, we examined the associations of 1-year fold changes in albuminuria with subsequent incident CKD (>25% decrease in eGFR reaching <60 ml/min per 1.73 m2) and rapid eGFR decline (eGFR slope <-5 ml/min per 1.73 m2 per year) assessed using Cox models and logistic regression, respectively, with adjustment for confounders.

RESULTS

The mean age was 64 (SD, 10) years old; 97% were men, and 91% were diabetic. There was a nearly linear association between 1-year fold changes in albuminuria and incident CKD. The multivariable-adjusted hazard ratios (95% confidence intervals) of incident CKD associated with more than twofold decrease, 1.25- to twofold decrease, 1.25- to twofold increase, and more than twofold increase (versus <1.25-fold decrease to <1.25-fold increase) in albuminuria were 0.82 (95% confidence interval, 0.77 to 0.89), 0.93 (95% confidence interval, 0.86 to 1.00), 1.12 (95% confidence interval, 1.05 to 1.20), and 1.29 (95% confidence interval, 1.21 to 1.38), respectively. Qualitatively similar associations were present for rapid eGFR decline (adjusted odds ratios; 95% confidence intervals for corresponding albuminuria changes: adjusted odds ratio, 0.86; 95% confidence interval, 0.78 to 0.94; adjusted odds ratio, 0.98; 95% confidence interval, 0.89 to 1.07; adjusted odds ratio, 1.18; 95% confidence interval, 1.08 to 1.29; and adjusted odds ratio, 1.67; 95% confidence interval, 1.54 and 1.81, respectively).

CONCLUSIONS

Relative changes in albuminuria over a 1-year interval were linearly associated with subsequent risk of kidney outcomes. Additional studies are warranted to elucidate the underlying mechanisms of the observed associations and test whether active interventions to lower elevated albuminuria can improve kidney outcomes.

Pre-End-Stage Renal Disease Hemoglobin Variability Predicts Post-End-Stage Renal Disease Mortality in Patients Transitioning to Dialysis

BACKGROUND

Hemoglobin variability (Hb-var) has been associated with increased mortality both in non-dialysis dependent chronic kidney disease (NDD-CKD) and end-stage renal disease (ESRD) patients. However, the impact of Hb-var in advanced NDD-CKD on outcomes after dialysis initiation remains unknown.

METHODS

Among 11,872 US veterans with advanced NDD-CKD transitioning to dialysis between October 2007 through September 2011, we assessed Hb-var calculated from the residual SD of at least 3 Hb values during the last 6 months before dialysis initiation (prelude period) using within-subject linear regression models, and stratified into quartiles. Outcomes included post-transition all-cause, cardiovascular, and infection-related mortality, assessed in Cox proportional hazards models and adjusted for demographics, comorbidities, length of hospitalization, medications, estimated glomerular filtration rate (eGFR), type of vascular access, Hb parameters (baseline Hb [i.e., intercept] and change in Hb [i.e., slope]), and number of Hb measurements.

RESULTS

Higher prelude Hb-var was associated with use of iron and antiplatelet agents, tunneled dialysis catheter use, higher levels of baseline Hb, change in Hb, eGFR, and serum ferritin. After multivariable adjustment, higher prelude Hb-var was associated with higher post-ESRD all-cause and infection-related mortality, but not cardiovascular mortality (adjusted hazard ratios [95% CI] for the highest [vs. lowest] quartile of Hb-var, 1.10 [1.02-1.19], 1.28 [0.93-1.75], and 0.93 [0.79-1.10], respectively).

CONCLUSIONS

High pre-ESRD Hb-var is associated with higher mortality, particularly from infectious causes rather than cardiovascular causes. Further research is required to clarify the underlying mechanisms and true causal nature of the observed association.

Association of Restless Legs Syndrome With Incident Parkinson's Disease

Study Objectives

The association between restless legs syndrome (RLS) and Parkinson's disease (PD) has been extensively studied with inconclusive results; therefore, we prospectively examined the associations of the presence of RLS with development of incident PD.

Methods

From a nationally representative prospective cohort of almost 3.5 million US veterans (age: 60 ± 14 years, 93% male, median follow-up time of 7.8 years [interquartile range: 6.4-8.4 years]), we created a propensity-matched cohort of 100882 PD-free patients and examined the association between prevalent RLS and incident PD. This association was also assessed in the entire cohort. Associations were examined using Cox models.

Results

There were 68 incident PD events (0.13%, incidence rate 1.87 [1.48-2.37]/10000 patient-years) in the RLS-negative group, and 185 incident PD events (0.37%, incidence rate 4.72 [4.09-5.45]/10000 patient-years) in the RLS-positive group in the propensity-matched cohort. Prevalent RLS was associated with more than twofold higher risk of incident PD (hazard ratio [HR]: 2.57, 95% confidence interval [CI]: 1.95-3.39) compared to RLS-negative patients. Qualitatively similar results were found when we examined the entire 3.5 million cohort: Prevalent RLS was associated with more than twofold higher risk of incident PD (multivariable adjusted HR: 2.81, 95%CI: 2.41-3.27).

Conclusion

RLS and PD share common risk factors. In this large cohort of US veterans, we found that prevalent RLS is associated with higher risk of incident PD during 8 years of follow-up, suggesting that RLS could be an early clinical feature of incident PD.

Area-level poverty, race/ethnicity & dialysis star ratings

The Centers for Medicare and Medicaid Services recently released a five star rating system as part of ‘Dialysis Facility Compare’ to help patients identify and choose high performing clinics in the US. Eight dialysis-related measures determine ratings. Little is known about the association between surrounding community sociodemographic characteristics and star ratings. Using data from the U.S. Census and over 6000 dialysis clinics across the country, we examined the association between dialysis clinic star ratings and characteristics of the local population: 1) proportion of population below the federal poverty level (FPL); 2) proportion of black individuals; and 3) proportion of Hispanic individuals, by correlation and regression analyses. Secondary analyses with Quality Incentive Program (QIP) scores and population characteristics were also performed. We observed a negligible correlation between star ratings and the proportion of local individuals below FPL; Spearman coefficient, R = -0.09 (p<0.0001), and a stronger correlation between star ratings and the proportion of black individuals; R = -0.21 (p<0.0001). Ordered logistic regression analyses yielded adjusted odds ratio of 0.91 (95% confidence interval [0.80–1.30], p = 0.12) and 0.55 ([0.48–0.63], p<0.0001) for high vs. low level of proportion below FPL and proportion of black individuals, respectively. In contrast, a near-zero correlation was observed between star ratings and the proportion of Hispanic individuals. Correlations varied substantially by country region, clinic profit status and clinic size. Analyses using clinic QIP scores provided similar results. Sociodemographic characteristics of the surrounding community, factors typically outside of providers’ direct control, have varying levels of association with clinic dialysis star ratings.

Association of serum albumin level and venous thromboembolic events in a large cohort of patients with nephrotic syndrome

Background

Prior small studies have suggested an association between low serum albumin and increased risk of venous thromboembolic (VTE) events in patients with nephrotic syndrome (NS).

Methods

From a nationally representative prospective cohort of over 3 million US veterans with baseline estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m 2 , we identified 7037 patients with NS based on ICD-9 codes. Association between serum albumin and risk of incident VTE was assessed using Cox regression analysis with adjustments for age, gender, race, comorbidities, eGFR, body mass index and anticoagulant treatment.

Results

Mean age was 57 ± 11 years, patients were 96% male, 32% African-American and 60% diabetic. There were a total of 158 VTE events over a median follow-up of 8.1 years; 16 events [absolute event rate (AER) 4.1%, event rate 8.5/1000 patient-years (PY)] in patients with albumin <2.5 g/dL, 18 events (AER 3.4%, event rate 5.7/1000 patient-years) in patients with albumin 2.5-2.99 g/dL, 89 events (AER 2.5%, event rate 3.4/1000 patient-years) in patients with albumin 3-3.99 g/dL and 35 events (AER 1.4%, event rate 1.9/1000 patient-years) in patients with albumin ≥4 g/dL. Compared with patients with albumin ≥4 g/dL, those with albumin levels of 3-3.99 g/dL [adjusted hazard ratio (HR): 1.51, 95% confidence interval (CI): 1.01-2.26], 2.5-2.99 g/dL (HR: 2.24, 95% CI: 1.24-4.05) and <2.5 g/dL (HR: 2.79, 95% CI: 1.45-5.37) experienced a linearly higher risk of VTE events.

Conclusions

Lower serum albumin is a strong independent predictor for VTE events in NS. The risk increases proportionately with declining albumin levels. Clinical trials are needed to determine benefit of prophylactic anticoagulation in NS patients with moderately lower serum albumin levels.

Pre-ESRD Depression and Post-ESRD Mortality in Patients with Advanced CKD Transitioning to Dialysis

BACKGROUND AND OBJECTIVES

Depression in patients with nondialysis-dependent CKD is often undiagnosed, empirically overlooked, and associated with higher risk of death, progression to ESRD, and hospitalization. However, there is a paucity of evidence on the association between the presence of depression in patients with advanced nondialysis-dependent CKD and post-ESRD mortality, particularly among those in the transition period from late-stage nondialysis-dependent CKD to maintenance dialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

From a nation-wide cohort of 45,076 United States veterans who transitioned to ESRD over 4 contemporary years (November of 2007 to September of 2011), we identified 10,454 (23%) patients with a depression diagnosis during the predialysis period. We examined the association of pre-ESRD depression with all-cause mortality after transition to dialysis using Cox proportional hazards models adjusted for sociodemographics, comorbidities, and medications.

RESULTS

Patients were 72±11 years old (mean±SD) and included 95% men, 66% patients with diabetes, and 23% blacks. The crude mortality rate was similar in patients with depression (289/1000 patient-years; 95% confidence interval, 282 to 297) versus patients without depression (286/1000 patient-years; 95% confidence interval, 282 to 290). Compared with patients without depression, patients with depression had a 6% higher all-cause mortality risk in the adjusted model (hazard ratio, 1.06; 95% confidence interval, 1.03 to 1.09). Similar results were found across all selected subgroups as well as in sensitivity analyses using alternate definitions of depression.

CONCLUSION

Pre-ESRD depression has a weak association with post-ESRD mortality in veterans transitioning to dialysis.

Quality and Equitable Health Care Gaps for Women: Attributions to Sex Differences in Cardiovascular Medicine

The present review synthesizes evidence and discusses issues related to health care quality and equity for women, including minority population subgroups. The principle of "sameness" or women and men receiving equitable, high-quality care is a near-term target, but optimal population health cannot be achieved without consideration of the unique, gendered structural determinants of health and the development of unique care pathways optimized for women. The aim of this review is to promote enhanced awareness, develop critical thinking in sex and gender science, and identify strategic pathways to improve the cardiovascular health of women. Delineation of the components of high-quality health care, including a women-specific research agenda, remains a vital part of strategic planning to improve the lives of women at risk for or living with cardiovascular disease.

Blood Pressure Before Initiation of Maintenance Dialysis and Subsequent Mortality

BACKGROUND

Mortality is extremely high immediately after the transition to dialysis therapy, but the association of blood pressure (BP) before dialysis therapy initiation with mortality after dialysis therapy initiation remains unknown.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

17,729 US veterans transitioning to dialysis therapy in October 2007 to September 2011, with a median follow-up of 2.0 years.

PREDICTOR

Systolic (SBP) and diastolic BP (DBP) averaged over the last 1-year predialysis transition period as 6 (<120 to ≥160mmHg in 10-mmHg increments) and 5 (<60 to ≥90mmHg in 10-mmHg increments) categories, respectively, and as continuous measures.

OUTCOMES & MEASUREMENTS

Postdialysis all-cause mortality, assessed over different follow-up periods (ie, <3, 3-<6, 6-<12, and ≥12 months after dialysis therapy initiation) using Cox regressions adjusted for demographics, comorbid conditions, medications, cardiovascular medication adherence, body mass index, estimated glomerular filtration rate, and type of vascular access.

RESULTS

Mean predialysis SBP and DBP were 141.2±16.1 (SD) and 73.7±10.6mmHg, respectively. There was a reverse J-shaped association of SBP with all-cause mortality, with significantly higher mortality seen with SBP<140mmHg. Mortality risks associated with lower SBP were greatest in the first 3 months after dialysis therapy initiation, with multivariable-adjusted HRs of 2.40 (95% CI, 1.96-2.93), 1.99 (95% CI, 1.66-2.40), 1.35 (95% CI, 1.13-1.62), 0.98 (95% CI, 0.78-1.22), and 0.76 (95% CI, 0.57-1.00) for SBP <120, 120 to <130, 130 to <140, 150 to <160, and ≥160 (vs 140-<150) mmHg, respectively. No consistent association was observed between predialysis DBP and postdialysis mortality.

LIMITATIONS

Results cannot be inferred to show causality and may not be generalizable to women or the general US population.

CONCLUSIONS

Lower predialysis SBP is associated with higher all-cause mortality in the immediate postdialysis period. Predialysis DBP showed no consistent association with postdialysis mortality. Further studies are needed to clarify ideal predialysis SBP levels among incident dialysis patients as a potential means to improve the excessively high early dialysis mortality.

APOL1 Gene Kidney Risk Variants and Cardiovascular Disease: Getting to the Heart of the Matter

Apolipoprotein L1 gene (APOL1) renal risk variants exhibit strong genetic associations with a spectrum of nondiabetic kidney diseases in individuals with recent African ancestry. Relationships between APOL1 kidney risk variants and cardiovascular disease (CVD) susceptibility and CVD-related death remain controversial. Some studies detected an increased risk for CVD, whereas others support protection from death and subclinical CVD and cerebrovascular disease. Because treatments for nondiabetic kidney disease may target this gene and its protein products, it remains critical to clarify the potential extrarenal effects of APOL1 kidney risk variants. This review addresses the current literature on APOL1 associations with CVD, cerebrovascular disease, and death. Potential causes of disparate results between studies are discussed.

Heart Failure Increases the Risk of Adverse Renal Outcomes in Patients With Normal Kidney Function

BACKGROUND

Heart failure (HF) is associated with poor cardiac outcomes and mortality. It is not known whether HF leads to poor renal outcomes in patients with normal kidney function. We hypothesized that HF is associated with worse long-term renal outcomes.

METHODS AND RESULTS

Among 3 570 865 US veterans with estimated glomerular filtration rate (eGFR) ≥60 mL min-1 1.73 m-2 during October 1, 2004 to September 30, 2006, we identified 156 743 with an International Classification of Diseases, Ninth Revision, diagnosis of HF. We examined the association of HF with incident chronic kidney disease (CKD), the composite of incident CKD or mortality, and rapid rate of eGFR decline (slopes steeper than -5 mL min-1 1.73 m-2 y-1) using Cox proportional hazard analyses and logistic regression. Adjustments were made for various confounders. The mean±standard deviation baseline age and eGFR of HF patients were 68±11 years and 78±14 mL min-1 1.73 m-2 and in patients without HF were 59±14 years and 84±16 mL min-1 1.73 m-2, respectively. HF patients had higher prevalence of hypertension, diabetes mellitus, cardiac, peripheral vascular and chronic lung diseases, stroke, and dementia. Incidence of CKD was 69.0/1000 patient-years in HF patients versus 14.5/1000 patient-years in patients without HF, and 22% of patients with HF had rapid decline in eGFR compared with 8.5% in patients without HF. HF patients had a 2.12-, 2.06-, and 2.13-fold higher multivariable-adjusted risk of incident CKD, composite of CKD or mortality, and rapid eGFR decline, respectively.

CONCLUSIONS

HF is associated with significantly higher risk of incident CKD, incident CKD or mortality, and rapid eGFR decline. Early diagnosis and management of HF could help reduce the risk of long-term renal complications.

Ethnicity and the first diagnosis of a wide range of cardiovascular diseases: Associations in a linked electronic health record cohort of 1 million patients

BACKGROUND

While the association of ethnic group with individual cardiovascular diseases has been studied, little is known about ethnic differences in the initial lifetime presentation of clinical cardiovascular disease in contemporary populations.

METHODS AND RESULTS

We studied 1,068,318 people, aged ≥30 years and free from diagnosed CVD at baseline (90.9% White, 3.6% South Asian and 2.9% Black), using English linked electronic health records covering primary care, hospital admissions, acute coronary syndrome registry and mortality registry (CALIBER platform). During 5.7 years median follow-up between 1997-2010, 95,224 people experienced an incident cardiovascular diagnosis. 69.9% (67.2%-72.4%) of initial presentation in South Asian <60 yrs were coronary heart disease presentations compared to 47.8% (47.3%-48.3%) in White and 40.1% (36.3%-43.9%) in Black patients. Compared to White patients, Black patients had significantly lower age-sex adjusted hazard ratios (HRs) for initial lifetime presentation of all the coronary disease diagnoses (stable angina HR 0.80 (95% CI 0.68-0.93); unstable angina- 0.75 (0.59-0.97); myocardial infarction 0.49 (0.40-0.62)) while South Asian patients had significantly higher HRs (stable angina- 1.67 (1.52-1.84); unstable angina 1.82 (1.56-2.13); myocardial infarction- 1.67 (1.49-1.87). We found no ethnic differences in initial presentation with heart failure (Black 0.97 (0.79-1.20); S Asian 1.04(0.87-1.26)). Compared to White patients, Black patients were more likely to present with ischaemic stroke (1.24 (0.97-1.58)) and intracerebral haemorrhage (1.44 (0.97-2.12)). Presentation with peripheral arterial disease was less likely for Black (0.63 (0.50-0.80)) and South Asian patients (0.70 (0.57-0.86)) compared with White patients.

DISCUSSION

While we found the anticipated substantial predominance of coronary heart disease presentations in South Asian and predominance of stroke presentations in Black patients, we found no ethnic differences in presentation with heart failure. We consider the public health and research implications of our findings.

TRIAL REGISTRATION

NCT02176174, www.clinicaltrials.gov.

Ethnicity, lipids and cardiovascular disease

PURPOSE OF REVIEW

The prevalence of cardiovascular disease differs among ethnic groups and along geographic boundaries. At present, most of the projected increase in mortality from cardiovascular disease occurs in sub-Saharan African, Chinese and Southeast Asian populations. Ethnic disparities in the prevalence of cardiovascular disease coincide with quantitative and qualitative differences in risk factors for cardiovascular disease. High plasma cholesterol is one of the most important preventable causes of ischemic heart disease.

RECENT FINDINGS

The current review summarizes recent evidence on ethnic differences in ischemic heart disease and its correlates with genetic and acquired differences in plasma lipid and lipoprotein levels. The nature of ethnic differences in plasma lipid levels, apolipoprotein L1 en lipoprotein(a) [Lp(a)] is outlined, and the effects of lipid-lowering therapy and future efforts and challenges regarding implementation are discussed.

SUMMARY

Ethnic differences in HDL-cholesterol (HDL-C), triglyceride levels and Lp(a) may impact ethnic differences in cardiovascular disease and result in higher residual risk during lipid-lowering therapy. Further efforts should be made to stimulate the use of statins in both high-income and low-income countries and study their effects in individuals with different ethnic backgrounds.

Effect of Age on the Association of Vascular Access Type with Mortality in a Cohort of Incident End-Stage Renal Disease Patients

BACKGROUND/AIMS

All hemodialysis (HD) patients are generally recommended to create a fistula first; but to create a mature arteriovenous fistula (AVF) can be challenging in elderly individuals. It is unclear if elderly incident HD patients derive a survival benefit from an AVF over an arteriovenous graft (AVG) or a tunneled central venous catheter (TDC).

METHODS

We examined the association of vascular access type (AVF, AVG, and TDC with and without a maturing AVF/AVG at dialysis transition) at HD initiation with all-cause, cardiovascular (CV), and infection-related mortality in 46,786 US veterans using Cox models with adjustment for confounders. Effect modification by age was examined by examining associations in pre-specified age subgroups (<60, 60-<70, 70-<80, and ≥80 years old), and by including interaction terms.

RESULTS

Patients numbering 8,940 (19%) started HD with an AVF, 1,090 (3%) with an AVG, 8,262 (18%) with a TDC and a maturing AVF/AVG and 28,494 (61%) with a TDC without a maturing AVF/AVG. A total of 13,303 all-cause, 4,392 CV, and 1,058 infection-related deaths were observed in the first year after HD transition. Compared to patients with AVF, those with AVG and TDC with and without maturing AVF/AVG had incrementally higher overall risk of all-cause mortality and CV mortality. Only TDC use was associated with higher infection-associated mortality. These associations were not modified by age.

CONCLUSION

Although most of our patients consisted of male veterans and the results may not be generalized to the general population, the use of TDCs is associated with poor outcomes even in the most elderly incident HD patients.

Association of cumulative social risk with mortality and adverse cardiovascular disease outcomes

BACKGROUND

Quantifying the cumulative effect of social risk factors on cardiovascular disease (CVD) risk can help to better understand the sources of disparities in health outcomes.

METHOD AND RESULTS

Data from the Heart Strategies Concentrating on Risk Evaluation (HeartSCORE) study were used to create an index of cumulative social risk (CSR) and quantify its association with incident CVD and all-cause mortality. CSR was defined by assigning a score of 1 for the presence of each of 4 social factors: i) racial minority status (Black race), ii) single living status, iii) low income, and iv) low educational level. Hazard ratios (HRs) were computed using Cox-regression models, adjusted for CVD risk factors. Over a median follow-up period of 8.3 years, 127 incident events were observed. The incidence of the primary outcome for subgroups of participants with 0, 1, and ≥2 CSR scores was 5.31 (95% CI, 3.40-7.22), 10.32 (7.16-13.49) and 17.80 (12.94-22.67) per 1000 person-years, respectively. Individuals with CSR score of 1 had an adjusted HR of 1.85 (1.15-2.97) for incident primary outcomes, compared to those with score of 0. The corresponding HR for individuals with CSR score of 2 or more was 2.58 (1.60-4.17).

CONCLUSION

An accumulation of social risk factors independently increased the likelihood of CVD events and deaths in a cohort of White and Black individuals.

Hemodialysis Disparities in African Americans: The Deeply Integrated Concept of Race in the Social Fabric of Our Society

End-stage renal disease (ESRD) is one of the starkest examples of racial/ethnic disparities in health. Racial/ethnic minorities are 1.5 to nearly 4 times more likely than their non-Hispanic White counterparts to require renal replacement therapy (RRT), with African Americans suffering from the highest rates of ESRD. Despite improvements over the last 25 years, substantial racial differences are persistent in dialysis quality measures such as RRT modality options, dialysis adequacy, anemia, mineral and bone disease, vascular access, and pre-ESRD care. This report will outline the current status of racial disparities in key ESRD quality measures and explore the impact of race. While the term race represents a social construct, its association with health is more complex. Multiple individual and community level social determinants of health are defined by the social positioning of race in the U.S., while biologic differences may reflect distinct epigenetic changes and linkages to ancestral geographic origins. Together, these factors conspire to influence dialysis outcomes among African Americans with ESRD.

Renal Replacement Therapy and Incremental Hemodialysis for Veterans with Advanced Chronic Kidney Disease

Each year approximately 13,000 Veterans transition to maintenance dialysis, mostly in the traditional form of thrice-weekly hemodialysis from the start. Among >6000 dialysis units nationwide, there are currently approximately 70 Veterans Affairs (VA) dialysis centers. Given this number of VA dialysis centers and their limited capacity, only 10% of all incident dialysis Veterans initiate treatment in a VA center. Evidence suggests that, among Veterans, the receipt of care within the VA system is associated with favorable outcomes, potentially because of the enhanced access to healthcare resources. Data from the United States Renal Data System Special Study Center "Transition-of-Care-in-CKD" suggest that Veterans who receive dialysis in a VA unit exhibit greater survival compared with the non-VA centers. Substantial financial expenditures arise from the high volume of outsourced care and higher dialysis reimbursement paid by the VA than by Medicare to outsourced providers. Given the exceedingly high mortality and abrupt decline in residual kidney function (RKF) in the first dialysis year, it is possible that incremental transition to dialysis through an initial twice-weekly hemodialysis regimen might preserve RKF, prolong vascular access longevity, improve patients' quality of life, and be a more patient-centered approach, more consistent with "personalized" dialysis. Broad implementation of incremental dialysis might also result in more Veterans receiving care within a VA dialysis unit. Controlled trials are needed to examine the safety and efficacy of incremental hemodialysis in Veterans and other populations; the administrative and health care as well as provider structure within the VA system would facilitate the performance of such trials.

Early Mortality Associated with Inpatient versus Outpatient Hemodialysis Initiation in a Large Cohort of US Veterans with Incident End-Stage Renal Disease

BACKGROUND

Mortality in the immediate post-hemodialysis transition period is extremely high. Many end-stage renal disease (ESRD) patients in the US start dialysis in an inpatient setting, but the characteristics of patients starting dialysis as inpatients, and the association of inpatient hemodialysis transition with mortality remain unclear.

METHODS

We examined 48,261 US veterans who transitioned to hemodialysis between October 2007 and September 2011. Associations of inpatient hemodialysis starting with all-cause mortality were examined in Cox proportional hazard models, with adjustments for demographics, comorbidities, vascular access type, pre-dialysis nephrology care and medication use, and last pre-ESRD estimated glomerular filtration rate and hemoglobin.

RESULTS

A total of 22,338 (46.3%) patients received the first hemodialysis treatment in an inpatient setting. Inpatient hemodialysis transition was associated with older age, presence of a tunneled catheter, higher comorbidity burden, and lack of pre-dialysis nephrology care. A total of 8,674 patients died (mortality rate 405/1,000 patient-years, 95% CI 397-413) during the first 6 months after transition to hemodialysis. The starting of inpatient vs. outpatient hemodialysis was associated with significantly higher crude all-cause mortality, but this association was attenuated after multivariable adjustments.

CONCLUSIONS

Transition to hemodialysis in an inpatient setting is more common in older and sicker individuals, and in patients without pre-dialysis nephrology care and those who used a catheter for vascular access. Future studies are needed to determine if a higher proportion of patients could start hemodialysis treatment in outpatient clinics, through interventions targeting modifiable risk factors such as timely vascular access placement or earlier nephrology referrals.

The Affordable Care Act: implications for health-care equity

Inequalities in medical care are endemic in the USA. The Affordable Care Act (ACA), passed in 2010 and fully implemented in 2014, was intended to expand coverage and bring about a new era of health-care access. In this review, we evaluate the legislation's impact on health-care equity. We consider the law's coverage expansion, insurance market reforms, cost and affordability provisions, and delivery-system reforms. Although the ACA improved coverage and access-particularly for poorer Americans, women, and minorities-its overall impact was modest in comparison with the gaps present before the law's implementation. Today, 29 million people in the USA remain uninsured, and substantial inequalities in access along economic, gender, and racial lines persist. Although most Americans agree that further reform is needed, the proper direction for reform-especially following the 2016 presidential election-is highly contentious. We discuss proposals for change from opposite sides of the political spectrum, together with their potential impact on health equity.

Racial-ethnic disparities in mortality and kidney transplant outcomes among pediatric dialysis patients

BACKGROUND

Previous studies in adult hemodialysis patients have shown that African-American and Hispanic patients have a lower risk of mortality in addition to a lower likelihood of kidney transplantation. However, studies of the association between race and outcomes in pediatric dialysis are sparse and often do not examine outcomes in Hispanic children. The objective was to determine if racial-ethnic disparities in mortality and kidney transplantation outcomes exist in pediatric dialysis patients.

METHODS

This was a retrospective cohort analysis of 2,697 pediatric dialysis patients (aged 0-20 years) from a large national dialysis organization (entry period 2001-2011) of non-Hispanic white, African-American, and Hispanic race-ethnicity. Associations between race-ethnicity with mortality and kidney transplantation outcomes were examined separately using competing risks methods. Logistic regression analyses were used to examine the association between race-ethnicity, with outcomes within 1 year of dialysis initiation.

RESULTS

Of the 2,697 pediatric patients in this cohort, 895 were African-American, 778 were Hispanic, and 1,024 were non-Hispanic white. After adjusting for baseline demographics, competing risk survival analysis revealed that compared with non-Hispanic whites, African-Americans had a 64 % higher mortality risk (hazards ratio [HR] = 1.64; 95 % CI 1.24-2.17), whereas Hispanics had a 31 % lower mortality risk (HR = 0.69; 95 % CI 0.47-1.01) that did not reach statistical significance. African-Americans also had higher odds of 1-year mortality after starting dialysis (odds ratio [OR] = 2.08; 95 % CI 0.95-4.58), whereas both African-Americans and Hispanics had a lower odds of receiving a transplant within 1 year of starting dialysis (OR = 0.28; 95 % CI 0.19-0.41 and OR = 0.43; 95 % CI 0.31-0.59 respectively).

CONCLUSION

In contrast to adults, African-American pediatric dialysis patients have worse survival than their non-Hispanic white counterparts, whereas Hispanics have a similar to lower mortality risk. Both African-American and Hispanic pediatric dialysis patients had a lower likelihood of kidney transplantation than non-Hispanic whites, similar to observations in the adult dialysis population.

Race, Serum Potassium, and Associations With ESRD and Mortality

BACKGROUND

Recent studies suggest that potassium levels may differ by race. The basis for these differences and whether associations between potassium levels and adverse outcomes differ by race are unknown.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

Associations between race and potassium level and the interaction of race and potassium level with outcomes were investigated in the Racial and Cardiovascular Risk Anomalies in Chronic Kidney Disease (RCAV) Study, a cohort of US veterans (N=2,662,462). Associations between African ancestry and potassium level were investigated in African Americans in the Atherosclerosis Risk in Communities (ARIC) Study (N=3,450).

PREDICTORS

Race (African American vs non-African American and percent African ancestry) for cross-sectional analysis; serum potassium level for longitudinal analysis.

OUTCOMES

Potassium level for cross-sectional analysis; mortality and end-stage renal disease for longitudinal analysis.

RESULTS

The RCAV cohort was 18% African American (N=470,985). Potassium levels on average were 0.162mmol/L lower in African Americans compared with non-African Americans, with differences persisting after adjustment for demographics, comorbid conditions, and potassium-altering medication use. In the ARIC Study, higher African ancestry was related to lower potassium levels (-0.027mmol/L per each 10% African ancestry). In both race groups, higher and lower potassium levels were associated with mortality. Compared to potassium level of 4.2mmol/L, mortality risk associated with lower potassium levels was lower in African Americans versus non-African Americans, whereas mortality risk associated with higher levels was slightly greater. Risk relationships between potassium and end-stage renal disease were weaker, with no difference by race.

LIMITATIONS

No data for potassium intake.

CONCLUSIONS

African Americans had slightly lower serum potassium levels than non-African Americans. Consistent associations between potassium levels and percent African ancestry may suggest a genetic component to these differences. Higher and lower serum potassium levels were associated with mortality in both racial groups.

Pre-ESRD Dementia and Post-ESRD Mortality in a Large Cohort of Incident Dialysis Patients

BACKGROUND

Conservative management may be a desirable option for elderly, fragile, or demented patients who reach end-stage renal disease (ESRD), yet some patients with dementia are placed on renal replacement therapy nonetheless.

METHODS

From a nationwide cohort of 45,076 US veterans who transitioned to ESRD over 4 contemporary years (October 1, 2007 to September 30, 2011), we identified 1,336 (3.0%) patients with International Classification of Diseases, Ninth Revision, Clinical Modification code-based dementia diagnosis during the prelude (predialysis) period. We examined the association of prelude dementia with all-cause mortality within the first 6 months following transition to dialysis, using a propensity-matched cohort and Cox proportional hazards models.

RESULTS

In the entire cohort, the overall mean ± standard deviation age at baseline was 72 ± 11 years, 95% were male, 23% were African-American, and 66% were diabetic. There were 8,080 (18.5%) deaths (mortality rate, 412; 95% confidence interval [CI], 403-421/1,000 patient-years) in the dementia-negative group, and 396 (29.6%) deaths (mortality rate, 708; 95% CI, 642-782/1,000 patient-years) in the dementia-positive group in the entire cohort in the first 6 months after dialysis initiation. Presence of dementia was associated with higher risk of all-cause mortality (adjusted hazard ratio, 1.25; 95% CI, 1.12-1.38) compared to dementia-free patients in the first 6 months after dialysis initiation.

CONCLUSION

Pre-ESRD dementia is associated with increased risk of early post-ESRD mortality in veterans transitioning to dialysis.

Racial Differences in Association of Serum Calcium with Mortality and Incident Cardio- and Cerebrovascular Events

CONTEXT

Abnormalities in calcium metabolism may potentially contribute to the development of vascular disease. Calcium metabolism may be different in African American (AA) vs white individuals, but the effect of race on the association of serum calcium with clinical outcomes remains unclear.

OBJECTIVE

This study sought to examine race-specific associations of serum calcium levels with mortality and with major incident cardiovascular events.

DESIGN AND SETTING

This was a historical cohort study in the U.S. Department of Veterans Affairs health care facilities.

PARTICIPANTS

Participants included veterans (n = 1 967 622) with estimated glomerular filtration rate ≥ 60 mL/min/1.73 m².

MAIN OUTCOME MEASURES

The association between serum calcium levels with all-cause mortality, incident coronary heart disease (CHD), and ischemic stroke incidence was examined in multivariable adjusted Cox proportional hazards models, including an interaction term for calcium and race.

RESULTS

The association of calcium with all-cause mortality was U-shaped in both AA and white patients, but race modified the association of calcium with all-cause mortality. Compared with white patients, AA patients experienced lower risk of mortality when calcium was ≥ 8.8 mg/dL, with a statistically significant interaction (P < .001). Conversely, AA vs white race was associated with higher mortality when calcium was < 8.8 mg/dL. Calcium showed no significant association with ischemic stroke or CHD in both races; and race did not modify these associations (P = .37 and 0.11, respectively for interaction term).

CONCLUSIONS

Race modified the U-shaped association between calcium and all-cause mortality. Serum calcium is not associated with incident stroke or CHD in either AA or white patients. The race-specific difference in the association of calcium levels with mortality warrants further examination.

Constipation and Incident CKD

Constipation is one of the most prevalent conditions in primary care settings and increases the risk of cardiovascular disease, potentially through processes mediated by altered gut microbiota. However, little is known about the association of constipation with CKD. In a nationwide cohort of 3,504,732 United States veterans with an eGFR ≥60 ml/min per 1.73 m², we examined the association of constipation status and severity (absent, mild, or moderate/severe), defined using diagnostic codes and laxative use, with incident CKD, incident ESRD, and change in eGFR in Cox models (for time-to-event analyses) and multinomial logistic regression models (for change in eGFR). Among patients, the mean (SD) age was 60.0 (14.1) years old; 93.2% of patients were men, and 24.7% were diabetic. After multivariable adjustments, compared with patients without constipation, patients with constipation had higher incidence rates of CKD (hazard ratio, 1.13; 95% confidence interval [95% CI], 1.11 to 1.14) and ESRD (hazard ratio, 1.09; 95% CI, 1.01 to 1.18) and faster eGFR decline (multinomial odds ratios for eGFR slope <-10, -10 to <-5, and -5 to <-1 versus -1 to <0 ml/min per 1.73 m² per year, 1.17; 95% CI, 1.14 to 1.20; 1.07; 95% CI, 1.04 to 1.09; and 1.01; 95% CI, 1.00 to 1.03, respectively). More severe constipation associated with an incrementally higher risk for each renal outcome. In conclusion, constipation status and severity associate with higher risk of incident CKD and ESRD and with progressive eGFR decline, independent of known risk factors. Further studies should elucidate the underlying mechanisms.

Increased Risk of Incident Chronic Kidney Disease, Cardiovascular Disease, and Mortality in Patients With Diabetes With Comorbid Depression

OBJECTIVE

It is not known if patients with diabetes with depression have an increased risk of chronic kidney disease (CKD). We examined the association between depression and incident CKD, mortality, and incident cardiovascular events in U.S. veterans with diabetes.

RESEARCH DESIGN AND METHODS

Among a nationally representative prospective cohort of >3 million U.S. veterans with baseline estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2, we identified 933,211 patients with diabetes. Diabetes was ascertained by an ICD-9-CM code for diabetes, an HbA1c >6.4%, or receiving antidiabetes medication during the inclusion period. Depression was defined by an ICD-9-CM code for depression or by antidepressant use during the inclusion period. Incident CKD was defined as two eGFR levels <60 mL/min/1.73 m2 separated by ≥90 days and a >25% decline in baseline eGFR. The associations between depression and outcomes were assessed using Cox proportional regression.

RESULTS

Depression was present in 340,806 patients at enrollment. Depressed patients were younger (61 ± 11 vs. 65 ± 11 years), had higher eGFR (84 ± 15 vs. 81 ± 14 mL/min/1.73 m2), but had more comorbidities. Incident CKD developed in 180,343 patients. Depression was associated with 20% higher risk of incident CKD (adjusted hazard ratio [aHR] and 95% CI: 1.20 [1.19-1.21]). Similarly, depression was associated with increased all-cause mortality (aHR and 95% CI: 1.25 [1.24-1.26]).

CONCLUSIONS

The presence of depression in patients with diabetes is associated with higher risk of developing CKD compared with nondepressed patients. Intervention studies should determine if effective treatment of depression in patients with diabetes would prevent major renal and cardiovascular complications.

Association of Systolic Blood Pressure Variability With Mortality, Coronary Heart Disease, Stroke, and Renal Disease

BACKGROUND

Intraindividual blood pressure (BP) fluctuates dynamically over time. Previous studies suggested an adverse link between greater visit-to-visit variability in systolic blood pressure (SBP) and various outcomes. However, these studies have significant limitations, such as a small size, inclusion of selected populations, and restricted outcomes.

OBJECTIVES

This study investigated the association of increased visit-to-visit variability and all-cause mortality, cardiovascular events, and end-stage renal disease (ESRD) in a large cohort of U.S. veterans.

METHODS

From among 3,285,684 U.S. veterans with and without hypertension and normal estimated glomerular filtration rates (eGFR) during 2005 and 2006, we identified 2,865,157 patients who had 8 or more outpatient BP measurements. Systolic blood pressure variability (SBPV) was measured using the SD of all SBP values (normally distributed) in 1 individual. Associations of SD quartiles (<10.3, 10.3 to 12.7, 12.7 to 15.6, and ≥15.6 mm Hg) with all-cause mortality, incident coronary heart disease (CHD), stroke, and ESRD was examined using Cox models adjusted for sociodemographic characteristics, baseline eGFR, comorbidities, body mass index, SBP, diastolic BP, and antihypertensive medication use.

RESULTS

Several sociodemographic variables (older age, male sex, African-American race, divorced or widowed status) and clinical characteristics (lower baseline eGFR, higher SBP and diastolic BP), and comorbidities (presence of diabetes, hypertension, cardiovascular disease, and lung disease) were all associated with higher intraindividual SBPV. The multivariable adjusted hazard ratios and 95% confidence intervals for SD quartiles 2 through 4 (compared with the first quartile) associated with all-cause mortality, CHD, stroke, and ESRD were incrementally higher.

CONCLUSIONS

Higher SBPV in individuals with and without hypertension was associated with increased risks of all-cause mortality, CHD, stroke, and ESRD. Further studies are needed to determine interventions that can lower SBPV and their impact on adverse health outcomes.

APOL1 renal-risk genotypes associate with longer hemodialysis survival in prevalent nondiabetic African American patients with end-stage renal disease

Relative to European Americans, evidence supports that African Americans with end-stage renal disease (ESRD) survive longer on dialysis. Renal-risk variants in the apolipoprotein L1 gene (APOL1), associated with nondiabetic nephropathy and less subclinical atherosclerosis, may contribute to dialysis outcomes. Here, APOL1 renal-risk variants were assessed for association with dialytic survival in 450 diabetic and 275 nondiabetic African American hemodialysis patients from Wake Forest and Emory School of Medicine outpatient facilities. Outcomes were provided by the ESRD Network 6-Southeastern Kidney Council Standardized Information Management System. Dates of death, receipt of a kidney transplant, and loss to follow-up were recorded. Outcomes were censored at the date of transplantation or through 1 July 2015. Multivariable Cox proportional hazards models were computed separately in patients with nondiabetic and diabetic ESRD, adjusting for the covariates age, gender, comorbidities, ancestry, and presence of an arteriovenous fistula or graft at dialysis initiation. In nondiabetic ESRD, patients with 2 (vs. 0/1) APOL1 renal-risk variants had significantly longer dialysis survival (hazard ratio 0.57), a pattern not observed in patients with diabetes-associated ESRD (hazard ratio 1.29). Thus, 2 APOL1 renal-risk variants are associated with longer dialysis survival in African Americans without diabetes, potentially relating to presence of renal-limited disease or less atherosclerosis.

Age, Race and Cardiovascular Outcomes in African American Veterans

BACKGROUND

In the general population, compared wtih their White peers, African Americans suffer premature all-cause and cardiovascular (CV) deaths, attributed in part to reduced access to care and lower socioeconomic status. Prior reports indicated younger (aged 35 to 44 years) African Americans had a signficantly greater age-adjusted risk of death. Recent studies suggest that in a more egalitarian health care structure than typical United States (US) health care structures, African Americans may have similar or even better CV outcomes, but the impact of age is less well-known.

METHODS

We examined age stratified all-cause mortality, and incident coronary heart disease (CHD) and ischemic stroke in 3,072,966 patients (547,441 African American and 2,525,525 White) with an estimated glomerular filtration rate (eGFR)>60 mL/min/1.73m(2) receiving care from the US Veterans Health Administration. Outcomes were examined in Cox models adjusted for demographics, comorbidities, kidney function, blood pressure, socioeconomics and indicators of the quality of health care delivery.

RESULTS

African Americans had an overall 30% lower all-cause mortality (P<.001) and 29% lower incidence of CHD (P<.001) and higher incidence of ischemic stroke (aHR, 95%CI: 1.16, 1.13-1.18, P<.001). The lower rates of mortality and CHD were strongest in younger African Americans and attenuated across patients aged ≥70 years. Stroke rates did not differ by race in persons aged <70 years.

CONCLUSIONS

Among patients with normal eGFR and receiving care in the Veterans Health Administration, younger African Americans had lower all-cause mortality and incidence of CHD and similar rates of stroke, independent of demographic, comorbidity and socioeconomic differences. The lower all-cause mortality persisted but attenuated with increasing age and the lower incidence of CHD ended at aged ≥80 years. The higher incidence of ischemic stroke in African Americans was driven by increasing risk in patients aged ≥70 years suggesting that the improved cardiovascular outcomes were most dramatic for younger African Americans.

Age and Outcomes Associated with BP in Patients with Incident CKD

BACKGROUND AND OBJECTIVES

Hypertension is the most important treatable risk factor for cardiovascular outcomes. Many patients with CKD are elderly, but the ideal BP in these individuals is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

From among 339,887 patients with incident eGFR<60 ml/min per 1.73 m(2), we examined associations of systolic BP (SBP) and diastolic BP (DBP) with all-cause mortality, incident coronary heart disease (CHD), ischemic strokes, and ESRD from the time of developing CKD until the end of follow-up (July 26, 2013, for mortality, CHD, and stroke, and December 31, 2011, for ESRD) in multivariable-adjusted survival models categorized by patients' age.

RESULTS

Of the total cohort, 300,424 (88%) had complete data for multivariable analysis. Both SBP and DBP showed a U-shaped association with mortality. SBP displayed a linear association with CHD, stroke, and ESRD, whereas DBP showed no consistent association with either. SBP>140 mmHg was associated with higher incidence of all examined outcomes, but with an incremental attenuation of the observed risk in older compared with younger patients (P<0.05 for interaction) The adjusted hazard ratios and 95% confidence intervals associated with SBP≥170 mmHg (compared with 130-139 mmHg) in patients <50, 50-59, 60-69, 70-79, and ≥80 years were 1.95 (1.34 to 2.84), 2.01 (1.75 to 2.30), 1.68 (1.49 to 1.89), 1.39 (1.25 to 1.54), and 1.30 (1.17 to 1.44), respectively. The risk of incident CHD, stroke, and ESRD was incrementally higher with higher SBP in patients aged <80 years but showed no consistent association in those aged ≥80 years (P<0.05 for interaction for all outcomes).

CONCLUSIONS

In veterans with incident CKD, SBP showed different associations in older versus younger patients. The association of higher SBP with adverse outcomes was present but markedly reduced in older individuals, especially in those aged ≥80 years. Elevated DBP showed no consistent association with vascular outcomes in patients with incident CKD.

Synergistic association of combined glycemic and blood pressure level with risk of complications in US veterans with diabetes

OBJECTIVES

Hemoglobin A1c levels less than 7.0% and systolic blood pressure (SBP) less than 140 mmHg are each associated with lower risk of vascular complications in patients with diabetes mellitus. Associations between combined A1c level and SBP categories and risk of mortality and morbidity in diabetic patients are not well characterized.

METHODS

We examined 891 670 US diabetic veterans with baseline estimated glomerular filtration rates more than 60 ml/min per 1.73 m (mean age 67 ± 11 years, 97% men, 17% African-Americans). The associations of mutually exclusive combined categories of A1c (<6.5, 6.5-6.9, 7.0-7.9, 8.0-8.9, 9.0-9.9, and ≥10%) and SBP (<100, 100-119, 120-139, 140-159, 160-179, and ≥180 mmHg) with the risk of all-cause mortality and incident chronic kidney disease (CKD), coronary heart disease, and stroke were examined in Cox models adjusted for baseline characteristics using patients with concomitant A1c 6.5-6.9% and SBP of 120-139 mmHg as the referent group.

RESULTS

A total of 221 529 (25%) patients died, and 178 588 (20%), 43 373 (5%) and 36 935 (4%) developed CKD, coronary heart disease and stroke, respectively, during a median follow-up of 7.4 years. SBP displayed a J-shaped association with each outcome except CKD risk that was linearly associated with SBP across all A1c categories. A1c above 7.0% was associated with monotonically worse outcomes for all end points in all SBP categories. Patients with the combined highest A1c and SBP levels experienced the worst outcomes.

CONCLUSION

SBP greater than 120-139 mmHg and A1c greater than 7.0% are associated with higher mortality and vascular complications in diabetic patients, independent of each other. Combined efforts to improve both glycemic and blood pressure control may synergistically improve outcomes in patients with normal kidney function.

Candidate Surrogate End Points for ESRD after AKI

AKI, a frequently transient condition, is not accepted by the US Food and Drug Association as an end point for drug registration trials. We assessed whether an intermediate-term change in eGFR after AKI has a sufficiently strong relationship with subsequent ESRD to serve as an alternative end point in trials of AKI prevention and/or treatment. Among 161,185 United States veterans undergoing major surgery between 2004 and 2011, we characterized in-hospital AKI by Kidney Disease Improving Global Outcomes creatinine criteria and decline in eGFR from prehospitalization to postdischarge time points and quantified associations of these values with ESRD and mortality over a median of 3.8 years. An eGFR decline of ≥30% at 30, 60, and 90 days after discharge occurred in 3.1%, 2.5%, and 2.6%, of survivors without AKI and 15.9%, 12.2%, and 11.7%, of survivors with AKI. For patients with in-hospital AKI compared with those with no AKI and stable eGFR, a 30% decline in eGFR at 30, 60, and 90 days after discharge demonstrated adjusted hazard ratios (95% confidence intervals) of ESRD of 5.60 (4.06 to 7.71), 6.42 (4.76 to 8.65), and 7.27 (5.14 to 10.27), with corresponding estimates for 40% decline in eGFR of 6.98 (5.21 to 9.35), 8.03 (6.11 to 10.56), and 10.95 (8.10 to 14.82). Risks for mortality were smaller but consistent in direction. A 30%-40% decline in eGFR after AKI could be a surrogate end point for ESRD in trials of AKI prevention and/or treatment, but additional trial evidence is needed.