BACKGROUND: Hispanic ethnic density (HED) is a marker of better health outcomes among Hispanic patients with chronic disease. It is unclear whether community HED is associated with mortality risk among ethnically diverse patients receiving maintenance hemodialysis. METHODS: A retrospective analysis of patients in the United States cohort of the Dialysis Outcomes and Practice Patterns Study (DOPPS) database (2011-2015) was conducted (n = 4226). DOPPS data was linked to the American Community Survey database by dialysis facility zip code to obtain % Hispanic residents (HED). One way ANOVA and Kruskal Wallis tests were used to estimate the association between tertiles of HED with individual demographic, clinical and adherence characteristics, and facility and community attributes. Multivariable Cox proportional hazards models were used to estimate the mortality hazard ratio (HR) and 95% CIs by tertile of HED, stratified by age; a sandwich estimator was used to account for facility clustering. RESULTS: Patients dialyzing in facilities located in the highest HED tertile communities were younger (61.4 vs. 64.4 years), more commonly non-White (62.4% vs. 22.1%), had fewer comorbidities, longer dialysis vintage, and were more adherent to dialysis treatment, but had fewer minutes of dialysis prescribed than those in the lowest tertile. Dialyzing in the highest HED tertile was associated with lower hazard of mortality (HR, 0.86; 95% CI, 0.72-1.00), but this association attenuated with the addition of individual race/ethnicity (HR, 0.92; 95% CI, 0.78-1.09). In multivariable age-stratified analyses, those younger than 64 showed a lower hazard for mortality in the highest (vs. lowest) HED tertile (HR, 0.66; 95% CI, 0.49-0.90). Null associations were observed among patients ≥ 64 years. CONCLUSIONS: Treating in communities with greater HED and racial/ethnic integration was associated with lower mortality among younger patients which points to neighborhood context and social cohesion as potential drivers of improved survival outcomes for patients receiving hemodialysis.

Background and objectives

Anemia management changed substantially among dialysis patients in the United States around the time of implementation of the new Centers for Medicare & Medicaid Services bundled payment system and erythropoiesis-stimulating agent (ESA) label change in 2011. Among these, average ferritin levels increased dramatically and have remained high since; this study sought to gain understanding of this sustained rise in ferritin levels.

Design, setting, participants, & measurements

Trends in mean ferritin, hemoglobin, IV iron dose, and ESA dose from 2009 to 2013 were examined in 9735 patients from 91 United States Dialysis Outcomes and Practice Patterns Study facilities. Linear mixed models were used to assess the extent to which intravenous (IV) iron and ESA dose accounted for patients' changes in ferritin over time.

Results

Mean ESA dose and hemoglobin levels declined throughout the study. Mean IV iron dose increased from 210 mg/mo in 2009-2010 to a peak of 280 mg/mo in 2011, then declined back to 200 mg/mo and remained stable from 2012 to 2013. Mean ferritin increased from 601 ng/ml in the third quarter of 2009 to 887 ng/ml in the first quarter of 2012; models suggest that higher IV iron dosing was a primary determinant during 2011, but lower ESA doses contributed to the sustained high ferritin levels thereafter. In a subset of 17 facilities that decreased IV iron dose in 2011, mean ferritin rose by 120 ng/ml to 764 ng/ml, which appeared to be primarily due to ESA reduction. Together, changes in IV iron and ESA doses accounted for 46% of the increase in ferritin over the study period.

Conclusions

In contrast to expectations, the rise in average IV iron dose did not persist beyond 2011. The sustained rise in ferritin levels in United States dialysis patients after policy changes in 2011, to average levels well in excess of 800 ng/ml, appeared to be partly due to reductions in ESA dosing and not solely IV iron dosing practices. The effect of these changes in ferritin on health outcomes requires further investigation.

Predialysis volume overload is the sum of interdialytic weight gain (IDWG) and residual postdialysis volume overload. It results mostly from failure to achieve an adequate volume status at the end of the dialysis session. Recent developments in bioimpedance spectroscopy and possibly relative plasma volume monitoring permit noninvasive volume status assessment in hemodialysis patients. A large proportion of patients have previously been shown to be chronically volume overloaded predialysis (defined as >15% above 'normal' extracellular fluid volume, equivalent to >2.5 liters on average), and to exhibit a more than twofold increased mortality risk. By contrast, the magnitude of the mortality risk associated with IDWG is much smaller and only evident with very large weight gains. Here we review the available evidence on volume overload and IDWG, and question the use of IDWG as an indicator of 'nonadherence' by describing its association with postdialysis volume depletion. We also demonstrate the relationship between IDWG, volume overload and predialysis serum sodium concentration, and comment on salt intake. Discriminating between volume overload and IDWG will likely lead to a more appropriate management of fluid withdrawal during dialysis. Consensually, the present authors agree that this discrimination should be among the primary goals for dialysis caretakers today. In consequence, we recommend objective measures of volume status beyond mere evaluations of IDWG.