US Dialysis Research Articles

The Role of Place in Disparities Affecting Black Men Receiving Hemodialysis

IntroductionBlack men are over-represented in the end stage kidney disease population and are at disproportionate risk of unfavorable outcomes. There is a paucity of investigation to elucidate the mediators of this risk. This study attempts to identify residential community attributes as a possible contributor.MethodsA post-hoc analysis of prospectively collected data from a cohort of Black men enrolled in the US Dialysis Outcomes and Practice Patterns Study (DOPPS), 2010-–2015, linked to the American Community Survey, by dialysis facility zip codes was undertaken. The exposure variable was the dialysis facility community composition as defined by percent Black residents. Negative binomial regression was used to estimate incidence rate ratio (IRR) of hospitalization (first outcome) for Black men in crude and adjusted models. Similarly, Cox proportional hazards modeling was used to estimate mortality (second outcome) for Black men by type of community.ResultsA total of 702 Black men receiving chronic hemodialysis were included in the study. Black men receiving hemodialysis in communities with greater proportions of Black residents had lower Charlson scores and fewer comorbidities, but a higher rate of hypertension. They had equivalent adherence to dialysis treatments, but a lower rate of arteriovenous fistula use and fewer dialysis minutes prescribed. Black men receiving dialysis in communities with a greater proportion of Black residents (per 10% increase) had higher adjusted hospitalization rates (IRR 1.09, 95% confidence interval [CI] 1.00–1.19) and mortality (hazard ratio [HR] 1.29, 95% CI 1.05–1.59).ConclusionsThis study supports the unique role of residential community as a risk factor for Black men with end stage kidney disease, showing higher hospitalization and mortality in those treating in Black versus non-Black communities, despite equivalent adherence and fewer comorbidities.

A faster decline of residual kidney function and erythropoietin stimulating agent hyporesponsiveness in incident hemodialysis patients.

Erythropoietin stimulating agents (ESA) hyporesposiveness has been associated with increased mortality in hemodialysis (HD) patients. However, the impact of decline of residual kidney function (RKF) on ESA hyporesposiveness has not been adequately elucidated among patients receiving HD. The associations of RKF decline with erythropoietin resistance index (ERI; average weekly ESA dose [units])/post-dialysis body weight [kg]/hemoglobin [g/dL]) were retrospectively examined across four strata of annual change in RKF (residual renal urea clearance [KRU] < -3.0, -3.0 to <-1.5, -1.5 to <0, ≥0 mL/min/1.73 m2 per year; urinary volume < -600, -600 to<-300, -300 to <0, ≥0 mL/day per year) using logistic regression models adjusted for clinical characteristics and laboratory variables in 5239 incident HD patients in a large US dialysis organization between 1 January 2007 and 31 December 2011. The median values of the annual change in KRU and urinary volume were -1.2 (interquartile range [IQR]: -2.8 to 0.1) mL/min/1.73 m2 per year and -250 (IQR: -600 to 100) mL/day per year. A faster KRU decline in the first year of HD was associated with higher odds for ESA hyporesponsiveness: KRU decline of <-3.0, -3.0 to <-1.5, and -1.5 to <0/min/1.73 m2 per year were associated with adjusted odds ratios (OR) of 2.07 (95% confidence interval [CI]: 1.66-2.58), 1.54 (95%CI: 1.28-1.85), and 1.26 (95%CI: 1.07-1.49), respectively (reference: ≥0 mL/min/1.73 m2 per year). These associations were consistent across strata of baseline KRU, age, sex, race, diabetes, congestive heart failure, hemoglobin, and serum albumin. Sensitivity analyses using urinary volume as another index of RKF showed consistent associations. A faster RKF decline during the first year of dialysis was associated with ESA hyporesponsiveness and low hemoglobin levels among incident HD patients.

Prevalence of Fluid Overload in a US Dialysis Population

Prevalence of Fluid Overload in a US Dialysis Population

Prevalence of SARS-CoV-2 antibodies in a large nationwide sample of patients on dialysis in the USA: a cross-sectional study

BackgroundMany patients receiving dialysis in the USA share the socioeconomic characteristics of underserved communities, and undergo routine monthly laboratory testing, facilitating a practical, unbiased, and repeatable assessment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence.MethodsFor this cross-sectional study, in partnership with a central laboratory that receives samples from approximately 1300 dialysis facilities across the USA, we tested the remainder plasma of 28 503 randomly selected adult patients receiving dialysis in July, 2020, using a spike protein receptor binding domain total antibody chemiluminescence assay (100% sensitivity, 99·8% specificity). We extracted data on age, sex, race and ethnicity, and residence and facility ZIP codes from the anonymised electronic health records, linking patient-level residence data with cumulative and daily cases and deaths per 100 000 population and with nasal swab test positivity rates. We standardised prevalence estimates according to the overall US dialysis and adult population, and present estimates for four prespecified strata (age, sex, region, and race and ethnicity).FindingsThe sampled population had similar age, sex, and race and ethnicity distribution to the US dialysis population, with a higher proportion of older people, men, and people living in majority Black and Hispanic neighbourhoods than in the US adult population. Seroprevalence of SARS-CoV-2 was 8·0% (95% CI 7·7–8·4) in the sample, 8·3% (8·0–8·6) when standardised to the US dialysis population, and 9·3% (8·8–9·9) when standardised to the US adult population. When standardised to the US dialysis population, seroprevalence ranged from 3·5% (3·1–3·9) in the west to 27·2% (25·9–28·5) in the northeast. Comparing seroprevalent and case counts per 100 000 population, we found that 9·2% (8·7–9·8) of seropositive patients were diagnosed. When compared with other measures of SARS-CoV-2 spread, seroprevalence correlated best with deaths per 100 000 population (Spearman's ρ=0·77). Residents of non-Hispanic Black and Hispanic neighbourhoods experienced higher odds of seropositivity (odds ratio 3·9 [95% CI 3·4–4·6] and 2·3 [1·9–2·6], respectively) compared with residents of predominantly non-Hispanic white neighbourhoods. Residents of neighbourhoods in the highest population density quintile experienced increased odds of seropositivity (10·3 [8·7–12·2]) compared with residents of the lowest density quintile. County mobility restrictions that reduced workplace visits by at least 5% in early March, 2020, were associated with lower odds of seropositivity in July, 2020 (0·4 [0·3–0·5]) when compared with a reduction of less than 5%.InterpretationDuring the first wave of the COVID-19 pandemic, fewer than 10% of the US adult population formed antibodies against SARS-CoV-2, and fewer than 10% of those with antibodies were diagnosed. Public health efforts to limit SARS-CoV-2 spread need to especially target racial and ethnic minority and densely populated communities.FundingAscend Clinical Laboratories.

Community Racial Composition and Hospitalization Among Patients Receiving In-Center Hemodialysis

Community racial composition has been shown to be associated with mortality in patients receiving maintenenance dialysis. It is unclear whether living in communities with predominantly Black residents is also associated with risk for hospitalization among patients receiving hemodialysis. Retrospective analysis of prospectively collected data from a cohort of patients receiving hemodialysis. 4,567 patients treated in 154 dialysis facilities located in 127 unique zip codes and enrolled in US Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4 to 5 (2010-2015). Tertile of percentage of Black residents within zip code of patients' dialysis facility, defined through a link to the American Community Survey. Rate of hospitalizations during the study period. Associations of patient-, facility-, and community-level variables with community's percentage of Black residents were assessed using analysis of variance, Kruskal-Wallis, or χ2/Fisher exact tests. Negative binomial regression was used to estimate the incidence rate ratio for hospitalizations between these communities, with and without adjustment for potential confounding variables. Mean age of study patients was 62.7 years. 53% were White, 27% were Black, and 45% were women. Median and threshold percentages of Black residents in zip codes in which dialysis facilities were located were 34.2% and≥14.4% for tertile 3 and 1.0% and≤1.8% for tertile 1, respectively. Compared with those in tertile 1 facilities, patients in tertile 3 facilities were more likely to be younger, be Black, live in urban communities with lower socioeconomic status, have a catheter as vascular access, and have fewer comorbid conditions. Patients dialyzing in communities with the highest tertile of Black residents experienced a higher adjusted rate of hospitalization (adjusted incidence rate ratio, 1.32; 95% CI, 1.12-1.56) compared with those treated in communities within the lowest tertile. Potential residual confounding. The risk for hospitalization for patients receiving maintenance dialysis is higher among those treated in communities with a higher percentage of Black residents after adjustment for dialysis care, patient demographics, and comorbid conditions. Understanding the cause of this association should be a priority of future investigation.

Effect of the ASCENT Intervention to Increase Knowledge of Kidney Allocation Policy Changes Among Dialysis Providers

IntroductionThe Allocation System Changes for Equity in Kidney Transplantation (ASCENT) trial was a cluster-randomized pragmatic, effectiveness-implementation study designed to test whether a multicomponent educational intervention targeting leadership, clinic staff, and patients in dialysis facilities improved knowledge and awareness of the 2014 Kidney Allocation System (KAS) change.MethodsParticipants included 690 dialysis facility medical directors, nephrologists, social workers, and other staff within 655 US dialysis facilities, with 51% (n = 334) in the intervention group and 49% (n = 321) in the control group. Intervention activities included a webinar targeting medical directors and facility staff, an approximately 10-minute educational video targeting dialysis staff, an approximately 10-minute educational video targeting patients, and a facility-specific audit and feedback report of transplant performance. The control group received a standard United Network for Organ Sharing brochure. Provider knowledge was a secondary outcome of the ASCENT trial and the primary outcome of this study; knowledge was assessed as a cumulative score on a 5-point Likert scale (higher score = greater knowledge). Intention-to-treat analysis was used.ResultsAt baseline, nonintervention providers had a higher mean knowledge score (mean ± SD, 2.45 ± 1.43) than intervention providers (mean ± SD, 2.31 ± 1.46). After 3 months, the average knowledge score was slightly higher in the intervention (mean ± SD, 3.14 ± 1.28) versus nonintervention providers (mean ± SD, 3.07 ± 1.24), and the estimated mean difference in knowledge scores between the groups at follow-up minus the mean difference at baseline was 0.25 (95% confidence interval [CI], 0.11–0.48; P = 0.039). The effect size (0.41) was low to moderate.ConclusionDialysis facility provider education could help extend the impact of a national policy change in organ allocation.

Incidence and risk factors for HPV-associated cancers in women with end-stage renal disease

Human papillomavirus (HPV) causes the majority of cervical, anal/rectal, and oropharyngeal cancers in women. End-stage renal disease (ESRD) is also associated with an increased risk of malignancy, but the incidence...

Concomitant Use of Gabapentinoids with Opioids Is Associated with Increased Mortality and Morbidity among Dialysis Patients

Background: The opioid epidemic is a public health emergency and appropriate medication prescription for pain remains challenging. Physicians have increasingly prescribed gabapentinoids for pain despite limited evidence supporting their use. We determined the prevalence of concomitant gabapentinoid and opioid prescriptions and evaluated their associations with outcomes among dialysis patients. Methods: We used the United States Renal Data System to identify patients treated with dialysis with Part A, B, and D coverage for all of 2010. Patients were grouped into 4 categories of drugs exposure status in 2010: (1) no prescriptions of either an opioid or gabapentinoid, (2) ≥1 prescription of an opioid and no prescriptions of gabapentinoids, (3) no prescriptions of an opioid and ≥1 prescription of gabapenbtinoids, (4) ≥1 prescription of both an opioid and gabapentinoid. Outcomes included 2-year all-cause death, dialysis discontinuation, and hospitalizations assessed in 2011 and 2012. Results: The study population included 153,758 dialysis patients. Concomitant prescription of an opioid and gabapentin (15%) was more common than concomitant prescription of an opioid and pregabalin (4%). In adjusted analyses, concomitant prescription of an opioid and gabapentin compared to no prescription of either was associated with increased risk of death (hazard ratio [HR] 1.16, 95% CI 1.12–1.19), dialysis discontinuation (HR 1.14, 95% CI 1.03–1.27), and hospitalization (HR 1.33, 95% CI 1.31–1.36). Concomitant prescription of an opioid and pregabalin compared to no prescription of either was associated with increased mortality (HR 1.22, 95% CI 1.16–1.28) and hospitalization (HR 1.37, 95% CI 1.33–1.41), but not dialysis discontinuation (HR 1.13, 95% CI 0.95–1.35). Prescription of opioids and gabepentinoids compared to only being prescribed opioids was associated with higher risk of hospitalizations, but not mortality, or dialysis discontinuation. Conclusions: Concomitant prescription of opioids and gabapentinoids among US dialysis patients is common, and both drugs have independent effects on outcomes. Future research should prospectively investigate the potential harms of such drugs and identify safer alternatives for treatment of pain in end-stage renal disease patients.

Glycemic Control and Infections Among US Hemodialysis Patients With Diabetes Mellitus

IntroductionPatients with diabetes mellitus (DM) on hemodialysis (HD) may be particularly vulnerable to infections.MethodsWe used merged data from the United States Renal Data System and electronic health records data from a large US dialysis provider to retrospectively examine the association between glycemic control and infections in these patients. Adult patients with DM aged ≥18 years who initiated in-center maintenance HD treatment from 2006 to 2011 and survived >90 days were included. Quarterly mean time-averaged hemoglobin A1c (HbA1c) values were categorized into <5.5%, 5.5 to <6.5%, 6.5 to <7.5%, 7.5 to <8.5%, and ≥8.5%. We used Medicare claims to ascertain infection-related outcomes and the ESRD Death Notification to identify death from infectious cause. We used Cox proportional hazards models to estimate multivariable-adjusted hazard ratios and 95% confidence intervals (CIs) for the associations between time-averaged HbA1c categories and infectious events.ResultsIn a cohort of 33,753 eligible patients, those with higher HbA1c levels had higher rates of diabetic foot infections and skin and soft tissue infections, with patients with HbA1c ≥8.5% having 23% (95% CI, 5%, 45%) and 22% (95% CI, 5%, 42%) higher rates, respectively, compared with HbA1c 5.5 to <6.5%. Patients in the lower HbA1c categories had higher rates of infection-related and all-cause mortality (P-for-trend <0.001).ConclusionThis study highlights the need for greater attention to foot evaluation and skin and soft tissue infections among patients on HD with less than optimal diabetes control.

Does Incident Solar Ultraviolet Radiation Lower Blood Pressure?

BackgroundHypertension remains a leading global cause for premature death and disease. Most treatment guidelines emphasize the importance of risk factors, but not all are known, modifiable, or easily avoided. Population blood pressure correlates with latitude and is lower in summer than winter. Seasonal variations in sunlight exposure account for these differences, with temperature believed to be the main contributor. Recent research indicates that UV light enhances nitric oxide availability by mobilizing storage forms in the skin, suggesting incident solar UV radiation may lower blood pressure. We tested this hypothesis by exploring the association between environmental UV exposure and systolic blood pressure (SBP) in a large cohort of chronic hemodialysis patients in whom SBP is determined regularly.Methods and ResultsWe studied 342 457 patients (36% black, 64% white) at 2178 US dialysis centers over 3 years. Incident UV radiation and temperature data for each clinic location were retrieved from the National Oceanic and Atmospheric Administration database. Linear mixed effects models with adjustment for ambient temperature, sex/age, body mass index, serum Na+/K+ and other covariates were fitted to each location and combined estimates of associations calculated using the DerSimonian and Laird procedure. Pre‐dialysis SBP varied by season and was ≈4 mm Hg higher in black patients. Temperature, UVA and UVB were all linearly and inversely associated with SBP. This relationship remained statistically significant after correcting for temperature.ConclusionsIn hemodialysis patients, in addition to environmental temperature, incident solar UV radiation is associated with lower SBP. This raises the possibility that insufficient sunlight is a new risk factor for hypertension, perhaps even in the general population.

Education Strategies in Dialysis Centers Associated With Increased Transplant Wait-listing Rates.

Transplant education in dialysis centers can increase access to kidney transplant; however, dialysis center transplant barriers are common, and limited research identifies the most effective transplant education approaches. We surveyed transplant educators in 1694 US dialysis centers about their transplant knowledge, use of 12 education practices, and 8 identified education barriers. Transplant wait-listing rates were calculated using US Renal Data System data. Fifty-two percent of educators orally recommended transplant to patients, 31% had in-center transplant discussions with patients, 17% distributed print educational resources, and 3% used intensive education approaches. Distribution of print education (incident rate ratio: 1.021.151.30) and using >1 intensive education practice (1.001.111.23) within dialysis centers were associated with increased wait-listing rates. Several dialysis center characteristics were associated with reduced odds of using education strategies leading to increased wait-listing. Centers with greater percentages of uninsured patients (odds ratio [OR]: 0.960.970.99), in rural locations (OR: 0.660.790.95), with for-profit ownership (OR: 0.640.770.91), and with more patients older than 65 years (OR: 0.050.110.23) had lower odds of recommending transplant, while centers with a higher patient-to-staff ratio were more likely to do so (OR: 1.011.031.04). Language barriers (OR: 0.480.640.86) and having competing work priorities (OR: 0.400.530.70) reduced the odds of distributing print education. Providers with greater transplant knowledge were more likely to use >1 intensive educational strategy (OR: 1.011.271.60) while providers who reported competing work priorities (OR: 0.510.660.84) and poor communication with transplant centers (OR: 0.580.760.98) were less likely to do so. Educators should prioritize transplant education strategies shown to be associated with increasing wait-listing rates.

Is It Time to Make Renal Transplantation Referral Mandatory?

In the last 2 decades, renal transplantation has been established as the best form of replacement therapy for most patients with end-stage kidney disease.1,2 Yet, the majority of patients who can benefit from renal transplantation are referred late or never referred to a transplant center.3 Barriers to referral have 3 different sources: the treating nephrologist, the patient, and the medical system. Often, treating physicians may have considered a transplant option but judged the patient to be too old or have many comorbidities to be eligible for renal transplantation. Sometimes, the nephrologists have to concentrate on the immediate initiation of dialysis due to the patient’s rapid deterioration of renal function. Patients have to overcome the complexity of the referral process that can be lengthy and exhausting, including medical suitability, pretransplant workup, and interest in transplantation, before they can be waitlisted. Some patients may simply give up or become too ill. Finally, there are both financial incentives and disincentives for nephrologists, dialysis centers, and eligibility for Medicare coverage for end-stage renal disease.4 It is important to point out that similarly restrictive practices to transplantation referral also exist in public healthcare systems such as in Canada and the United Kingdom.5,6 Part of the process to improve the effectiveness of the transplantation referral and waitlisting includes a comprehensive transplant education. In this issue of Transplantation, Waterman et al7 report on a survey of 1694 US dialysis centers, an extension of their prior work from 2015,8 on their educational practices and determined which are associated with increased waitlisting rates. The majority of the educators surveyed were female, Caucasian, and social workers. There were 12 transplant education practices and 8 reported barriers to providing transplant education assessed by the authors. Combined transplant education strategies such as distribution of print education and using >1 intensive education practice within dialysis centers were associated with higher waitlisting rates. This goes along with the Center for Medicare and Medicaid Services requirement for providers to inform patients of their transplant options within 45 days of initiating dialysis and a more recent Center for Medicare and Medicaid Service Technical Expert Panel requiring more specific metrics for transplant educational delivery in dialysis centers.9 The most important finding from this report is that a minority of centers used what is considered an intensive education approach which was associated with an increased odds ratio of waitlisting. The current study shows that a reduced odds ratio of using intensive education strategies is associated with centers having a greater percentage of uninsured patients, rural locations, for profit ownership, and dialysis patients >65 years old. Considering that the mortality rate of patients on dialysis at 5 years exceeds 60%,10 a timely referral and transplantation should be viewed with the same urgency perspective as for patients with other life threatening conditions. Perhaps we should review the process of mandatory information of transplant options and complement it with more intensive education practices and improved communication between dialysis and transplant centers. Perhaps the transplant community can encourage a change in the paradigm toward a form of mandatory referral of patients for a transplantation assessment. Transplant centers can help in the process of educating dialysis centers in better identifying eligibility of candidates and to rule out those with specific contraindications. Our patients certainly deserve to have every option to be able to make the best decision for their care. Increasing education of patients, patients' families, and general nephrologists about renal transplantation should harmonize practice and increase referral for renal transplantation. ACKNOWLEDGMENTs The authors wish to thank Andrea Herrera-Gayol, MD, MSc, PhD, for her critical review on the commentary.

Arteriovenous Fistula Use in the United States and Dialysis Facility–Level Comorbidity Burden

Patients with multiple comorbid conditions are less likely to use an arteriovenous fistula (AVF) for hemodialysis vascular access. Some dialysis facilities have high rates of AVF placement despite having patients with many comorbid conditions. This study describes variation in facility-level use of AVFs across the facility-level burden of patient comorbid conditions. Retrospective cohort study. Medicare patients receiving hemodialysis for 1 year or more in US dialysis facilities. Facility-level burden of patient comorbid conditions; patient characteristics. Odds of AVFs versus other access types; facility-level use of AVFs. Facility-level comorbidity burden was calculated by summing individual comorbid conditions, determining the average per patient, then defining 11 groups based on facility percentile ranking. Generalized estimating equations with a logit link were used to estimate the odds of AVF placement at the patient level. For the facility-level analysis, a generalized estimating equation model with the identity link was fit to characterize the percentage of AVF use at each facility. Overall, AVF use was 65.8% in 315,919 prevalent hemodialysis patients among 5,813 facilities. After adjustment for patient characteristics, AVF use was 0.27, 0.30, 1.05, and 1.74 percentage points lower than the median among facilities in the 61st to 70th, 71st to 80th, 81st to 90th, and 91st to 99th percentiles of comorbidity, respectively, and 0.42, 0.63, 1.34, and 1.90 percentage points higher than the median among facilities in the 31st to 40th, 21st to 30th, 11th to 20th, and 1st to 10th percentiles of comorbidity, respectively. Facilities in the greater than99th percentile of comorbidity burden had AVFuse that was 3.47 percentage points lower than the median. Facilities in the less than 1st percentile ofcomorbidity burden had AVF use that was 2.64 percentage points greater than the median. Limited to Medicare dialysis-dependent patients treated for 1 year or more. After adjustment for patient characteristics, we found small differences in facility rates of AVF use except in the extremes of high or low levels of comorbidity burden. Our study demonstrates that dialysis facilities with a relatively highpatient comorbidity burden can achieve similar fistula rates as facilities with healthier patients. Although high comorbidity burden does not explain low facility AVF use, additional study is needed to understand differences in AVF use rates between facilities with similar comorbidity burdens.

Racial and Ethnic Differences in Mortality Associated with Serum Potassium in Incident Peritoneal Dialysis Patients

Background: Abnormalities in serum potassium are risk factors for sudden cardiac death and arrhythmias among dialysis patients. Although a previous study in hemodialysis patients has shown that race/ethnicity may impact the relationship between serum potassium and mortality, the relationship remains unclear among peritoneal dialysis (PD) patients where the dynamics of serum potassium is more stable. Methods: Among 17,664 patients who started PD between January 1, 2007 and December 31, 2011 in a large US dialysis organization, we evaluated the association of serum potassium levels with all-cause and arrhythmia-related deaths across race/ethnicity using time-dependent Cox models with adjustments for demographics. We also used restricted cubic spline functions for serum potassium levels to explore non-linear associations. Results: Baseline serum potassium levels were the highest among Hispanics (4.2 ± 0.7 mEq/L) and lowest among non-Hispanic blacks (4.0 ± 0.7 mEq/L). Among 2,949 deaths during the follow-up of median 2.2 (interquartile ranges 1.3–3.2) years, 683 (23%) were arrhythmia-related deaths. Overall, both hyperkalemia and hypokalemia (i.e., serum potassium levels >5.0 and <3.5 mEq/L, respectively) were associated with higher all-cause and arrhythmia-related mortality. In a stratified analysis according to race/ethnicity, the association of hypokalemia with all-cause and arrhythmia-related mortality was consistent with an attenuation for arrhythmia-related mortality in non-Hispanic blacks. Hyperkalemia was associated with all-cause and arrhythmia-related mortality in non-Hispanic whites and non-Hispanic blacks, but no association was observed in Hispanics. Conclusion: Among incident PD patients, hypokalemia was consistently associated with all-cause and arrhythmia-related deaths irrespective of race/ethnicity. However, while hyperkalemia was associated with both death outcomes in non-Hispanic blacks and whites, it was not associated with either death outcome in Hispanic patients. Further studies are needed to demonstrate whether different strategies should be followed for the management of serum potassium levels according to race/ethnicity.

Association Between Dialysis Facility Ownership and Access to Kidney Transplantation

For-profit (vs nonprofit) dialysis facilities have historically had lower kidney transplantation rates, but it is unknown if the pattern holds for living donor and deceased donor kidney transplantation, varies by facility ownership, or has persisted over time in a nationally representative population. To determine the association between dialysis facility ownership and placement on the deceased donor kidney transplantation waiting list, receipt of a living donor kidney transplant, or receipt of a deceased donor kidney transplant. Retrospective cohort study that included 1 478 564 patients treated at 6511 US dialysis facilities. Adult patients with incident end-stage kidney disease from the US Renal Data System (2000-2016) were linked with facility ownership (Dialysis Facility Compare) and characteristics (Dialysis Facility Report). The primary exposure was dialysis facility ownership, which was categorized as nonprofit small chains, nonprofit independent facilities, for-profit large chains (>1000 facilities), for-profit small chains (<1000 facilities), and for-profit independent facilities. Access to kidney transplantation was defined as time from initiation of dialysis to placement on the deceased donor kidney transplantation waiting list, receipt of a living donor kidney transplant, or receipt of a deceased donor kidney transplant. Cumulative incidence differences and multivariable Cox models assessed the association between dialysis facility ownership and each outcome. Among 1 478 564 patients, the median age was 66 years (interquartile range, 55-76 years), with 55.3% male, and 28.1% non-Hispanic black patients. Eighty-seven percent of patients received care at a for-profit dialysis facility. A total of 109 030 patients (7.4%) received care at 435 nonprofit small chain facilities; 78 287 (5.3%) at 324 nonprofit independent facilities; 483 988 (32.7%) at 2239 facilities of large for-profit chain 1; 482 689 (32.6%) at 2082 facilities of large for-profit chain 2; 225 890 (15.3%) at 997 for-profit small chain facilities; and 98 680 (6.7%) at 434 for-profit independent facilities. During the study period, 121 680 patients (8.2%) were placed on the deceased donor waiting list, 23 762 (1.6%) received a living donor kidney transplant, and 49 290 (3.3%) received a deceased donor kidney transplant. For-profit facilities had lower 5-year cumulative incidence differences for each outcome vs nonprofit facilities (deceased donor waiting list: -13.2% [95% CI, -13.4% to -13.0%]; receipt of a living donor kidney transplant: -2.3% [95% CI, -2.4% to -2.3%]; and receipt of a deceased donor kidney transplant: -4.3% [95% CI, -4.4% to -4.2%]). Adjusted Cox analyses showed lower relative rates for each outcome among patients treated at all for-profit vs all nonprofit dialysis facilities: deceased donor waiting list (hazard ratio [HR], 0.36 [95% CI, 0.35 to 0.36]); receipt of a living donor kidney transplant (HR, 0.52 [95% CI, 0.51 to 0.54]); and receipt of a deceased donor kidney transplant (HR, 0.44 [95% CI, 0.44 to 0.45]). Among US patients with end-stage kidney disease, receiving dialysis at for-profit facilities compared with nonprofit facilities was associated with a lower likelihood of accessing kidney transplantation. Further research is needed to understand the mechanisms behind this association.

Computationally efficient inference for center effects based on restricted mean survival time.

Restricted mean survival time (RMST) has gained increased attention in biostatistical and clinical studies. Directly modeling RMST (as opposed to modeling then transforming the hazard function) is appealing computationally and in terms of interpreting covariate effects. We propose computationally convenient methods for evaluating center effects based on RMST. A multiplicative model for the RMST is assumed. Estimation proceeds through an algorithm analogous to stratification, which permits the evaluation of thousands of centers. We derive the asymptotic properties of the proposed estimators and evaluate finite sample performance through simulation. We demonstrate that considerable decreases in computational burden are achievable through the proposed methods, in terms of both storage requirements and run time. The methods are applied to evaluate more than 5000 US dialysis facilities using data from a national end-stage renal disease registry.

Disparities between trial cohorts and real-life patients.

A new study reports important differences between the characteristics of patients with end-stage renal disease on dialysis who are enrolled in clinical trials worldwide and the general US dialysis population. These findings highlight the importance of including older patients and those with comorbidities in clinical trials.

The Role Of Social Risk Factors In Dialysis Facility Ratings And Penalties Under A Medicare Quality Incentive Program.

Medicare's End-Stage Renal Disease Quality Incentive Program is a mandatory pay-for-performance program for US dialysis facilities, in which facilities are penalized up to 2percent of their total Medicare payments based on their performance on quality metrics. While analyses of similar programs in other settings have shown performance to be related to social risk factors, it is unknown whether this program displays similar patterns. In this national study, facilities located in low-income ZIP codes and with high proportions of patients who were black or dually enrolled in Medicaid had lower performance scores and higher rates of penalization under the program. Independent (versus chain) status, large facility size, and urban location were also associated with penalties. Further study is needed to determine the degree to which these patterns reflect low-quality care delivery versus patient factors beyond providers' control. In the meantime, the impact of these penalties on providers serving vulnerable populations should be tracked closely.

Serum albumin and hospitalization among pediatric patients with end-stage renal disease who started dialysis therapy.

Hypoalbuminemia is a strong predictor of hospitalization and mortality among adult dialysis patients. However, data are scant on the association between serum albumin and hospitalization among children new to dialysis. In a retrospective cohort study of children 1-17years old with end-stage renal disease receivingdialysis therapy in a large US dialysis organization 2007-2011, we examined the association of serum albumin with hospitalization frequency and total hospitalization days usinga negative binomial regression model. Among 416 eligible patients, median (interquartile range) age was 14 (10-16) years and mean ± SD baseline serum albumin level was 3.7 ± 0.8g/dL. Two hundred sixty-six patients (64%) were hospitalized during follow-up withan incidence rate of 2.2 (95%CI, 1.9-2.4)admissions per patient-year. There was a U-shaped association between serum albumin and hospitalization frequency; hospitalization rates (95%CI) were 2.7 (2.2-3.2), 1.9 (1.5-2.4), 1.6 (1.3-1.9), and 2.7 (1.7-3.6) per patient-year among patients with serum albumin levels < 3.5, 3.5- < 4.0, 4.0- < 4.5, and ≥ 4.5g/dL, respectively. Case mix-adjusted hospitalization incidence rate ratios (IRRs) (95%CI) were 1.63 (1.24-2.13), 1.32 (1.10-1.58), and 1.25 (1.06-1.49) at serum albumin levels 3.0, 3.5, and 4.5g/dL, respectively (reference: 4.0g/dL). Similar trends were observed in hospitalization days. These associations remained robust against further adjustment for laboratory variables associated with malnutrition and inflammation. Both high and low serum albumin were associated with higher hospitalization in children starting dialysis. Because the observed association is novel and not fully explainable especially for high serum albumin levels, interpreting the results requires caution and further studies are needed to confirm and elucidate this association before clinical recommendations are made.

Association of Hospitalization and Mortality Among Patients Initiating Dialysis With Hemodialysis Facility Ownership and Acquisitions

Mergers and acquisitions among health care institutions are increasingly common, and dialysis markets have undergone several decades of mergers and acquisitions. To examine the outcomes of hemodialysis facility acquisitions independent of associated changes in market competition resulting from acquisitions. Cohort study using difference-in-differences (DID) analyses to compare changes in health outcomes over time among in-center US dialysis facilities that were acquired by a hemodialysis chain with facilities located nearby but not acquired. Multivariable Cox proportional hazards regression models and negative binomial models with predicted marginal effects were developed to examine health outcomes, controlling for patient, facility, and geographic characteristics. All facility ownership types were examined together and stratified analyses were conducted of facilities that were independently owned and chain owned prior to acquisitions. The study was conducted from January 2001 to September 2015; 174 905 patients starting in-center dialysis in the 3 years before and following dialysis facility acquisitions were included. Data were analyzed from March 2017 to December 2018. Acquisition by a hemodialysis chain. Twelve-month hazard of death and hospital days per patient-year were the primary outcomes. Of the 174 905 patients included in the study, 79 705 were women (45.6%), 24 409 (14.0%) were of Hispanic ethnicity, 61 815 (35.3%) were black, 105 272 (60.2%) were white, and 1247 (0.7%) were Native American. Mean (SD) age was 65 (15) years. Before acquisitions, adjusted mortality and hospitalization rates were 10% (95% CI, -16% to -5%) and 2.9 days per patient-year (95% CI, -3.8 to -2.0) lower, respectively, at independently owned facilities that were acquired compared with those that were not acquired, while hospitalization rates were 0.7 days (95% CI, -1.2 to -2.0) lower at chain-owned facilities that were acquired compared with those that were not acquired. In stratified analyses of independently owned facilities, mortality decreases were smaller at acquired (-8.4%; 95% CI, -14% to -25%) vs nonacquired (-20.3%; 95% CI, -25.8% to -14.3%) facilities (DID P < .001). Similarly, hospitalization rates did not change at acquired facilities and decreased by 2.6 days per patient-year (95% CI, -3.6 to -1.7 days) at nonacquired facilities (DID P < .001). Acquisitions were not associated with changes in health outcomes at chain-owned facilities. Slower reductions in mortality and hospitalization rates at independently owned facilities contributed to significant differences in hospitalizations (-2.0 days; 95% CI, -2.5 to -1.6, at nonacquired vs 0.9 days; 95% CI, -1.3 to -0.5, at acquired facilities; DID, P < .001) across all ownership types but not mortality (DID, P = .28) with regard to acquisitions. Acquisition of independently owned dialysis facilities by larger dialysis organizations was associated with slower decreases in mortality and hospitalization rates, as nonacquired facilities appeared to experience more rapid improvements in outcomes over time.