Race and Mortality in Hemodialysis Patients in Brazil.

Rationale & Objective: Studies in the United States and United Kingdom generally report better survival for Black than White patients undergoing maintenance hemodialysis, a finding not explained by differences in sociodemographics or comorbid conditions. It is not clear if such findings can be generalized to other countries. We investigated the association between race and mortality among a Black, White, and Mixed-Race sample of maintenance hemodialysis patients in Salvador, Brazil. Study Design: Prospective cohort study. Baseline data collection from July 1, 2005 through December 31, 2010. The follow-up period ended on December 31, 2017. Setting & Participants: The Prospective Study of the Prognosis of Chronic Hemodialysis Patients (PROHEMO) is a cohort of 1,501 patients from 4 dialysis units in Salvador, Brazil. Predictor: Race categorized as White (12.9%), Mixed-Race (62.4%), and Black (24.8%), using White as the reference category. Outcome: Survival. Analytical Approach: Using Cox regression models, we tested the association between race and mortality, with adjustments for age, sex, social factors, laboratory results, and comorbid conditions. Results: The mean age was 49 years for Black and Mixed-Race patients and 55 years for White patients. In a Cox model adjusted for age, mortality did not differ between Black and White patients (HR, 1.10; 95% CI, 0.66-1.83) or between Mixed-Race and White patients (HR, 1.00; 95% CI, 0.65-1.54). Adjustment for sociodemographics and comorbid conditions had minimal impact on these results. Limitations: Potential residual confounding and lack of adjustment for time-varying variables. Conclusions: Contrary to studies in the United States and United Kingdom, we did not find racial difference in mortality among patients in our Brazilian setting who were being treated by maintenance hemodialysis. These results underscore the importance of investigating racial differences in mortality among patients undergoing maintenance hemodialysis in different populations and countries.

Vascular calcification by conventional X-ray and mortality in a cohort of predominantly African descent hemodialysis patients.

BACKGROUND/OBJECTIVE: There is a lack of studies describing the prevalence of vascular calcification (VC) and its association with mortality in maintenance hemodialysis (MHD) patients of African descent. We investigated if a VC score based on the number of calcified vascular beds was associated with mortality in MHD patients. METHODS: We analyzed data from 211 MHD patients enrolled from January 2010 to January 2011 in the prospective cohort study, "The Prospective Study of the Prognosis of Chronic Hemodialysis Patients (PROHEMO)," developed in Salvador, BA, Brazil. VC was evaluated using radiographs of the hands, abdomen, hip, and chest; the score was calculated by the number of calcified sites as 0 (absence of calcification), 1 (one calcified site), 2 (two sites), 3 (⩾3 sites). We used Cox's regression to estimate the hazard ratio (HR) and 95% confidence interval (CI) of associations between VC and mortality with adjustments for age and comorbidities. RESULTS: VC was detected in 114 (54.0%) patients; 37 (17.5%) with a VC score = 1; 21 (10%) with VC score = 2 and 56 (26.5%) with VC score = 3. Compared with VC score = 0, the adjusted hazard of death was 2.67 (95% CI: 1.12, 6.33) for patients with VC score = 1; HR = 2.89 (95% CI: 0.95, 7.63) for VC score = 2; and HR = 3.27 (95% CI: 1.47, 7.28) for VC score = 3. CONCLUSION: The present study in an African descent MHD population provides support for the VC score based on conventional radiography as a prediction tool for the clinical practice. As shown, the VC score was monotonically and independently associated with mortality.

The sickle cell trait and end stage renal disease in Salvador, Brazil.

BACKGROUND: Carriers of the sickle cell trait (HbAS) usually remain asymptomatic. However, under conditions of low tissue oxygenation, red blood cell sickling and vascular obstruction may develop. Chronic kidney disease (CKD) can arise from conditions promoting low-oxygen in kidney tissue, which may be aggravated by the presence of the sickle cell trait. In addition, CKD can arise from other genetic traits. AIM: To compare the frequency of HbAS among hemodialysis patients and the general newborn population of Salvador (Bahia-Brazil), as well as to investigate the frequencies of apolipoprotein L1 risk variants in patients undergoing hemodialysis. METHODS: A cross-sectional study included 306 patients with ESRD (End Stage Renal Disease) on hemodialysis for no more than three years. Hemoglobin profiles were characterized by high-performance liquid chromatography. To estimate the sickle cell trait frequency in the general population of Salvador, we analyzed data collected by a local neonatal screening program between 2011 and 2016. To exclude the potential contributing effect of the apolipoprotein L1 (APOL1) gene variants, we performed genotyping by PCR and DNA sequencing of 45 patients. RESULTS: The frequency of HbAS was significantly higher in hemodialysis patients (9.8%) than in the general population (4.6%): Odds Ratio = 2.32 (95% CI = 1.59-3.38). No differences in demographic, clinical or laboratory data were found among patients with or without the sickle cell trait. The frequency of patients with none, one or two APOL1 risk haplotypes (G1 and G2) for CKD were 80%, 18% and 2%, respectively. CONCLUSIONS: The frequency of the sickle cell trait is higher in patients with ESRD on hemodialysis compared to the general population. APOL1 haplotypes do not seem to be the determinant of ESRD in these patients.

Sex-age-specific handgrip strength and mortality in an incident hemodialysis cohort: The risk explained by nutrition and comorbidities.

OBJECTIVE:: To investigate associations of sex-age-specific handgrip strength by a dynamometer with all-cause mortality and the percent excess risk explained (%ERE) by comorbidities and nutritional indicators in incident maintenance hemodialysis patients. METHODS:: Prospective cohort of 413 adult patients (165 women, 248 men, 299 <60 years and 114 ⩾60 years) with <6 months (82% <3 months) on dialysis enrolled in PROHEMO in Salvador, Brazil. Low and high handgrip strength groups were based on sex-age-specific cutoffs (17.8 kg for women <60 years, 13.8 kg for women ⩾60 years, 29.5 kg for men <60 years, and 21.9 kg for men ⩾60 years). We used Cox regression to estimate the mortality hazard ratio. The %ERE was determined by the equation (HR1 - HR2)/(HR1 - 1) × 100, in which HR1 represented the hazard ratio in a model with a smaller number of covariates and HR2 represented the hazard ratio in a subsequent model with the inclusion of new covariates plus the variables included in the previous model. RESULTS:: The mortality hazard ratio comparing low and high handgrip strength was 2.58 (95% confidence interval: 1.73, 3.85) in the model with sociodemographic factors and vintage and 2.25 (95% confidence interval: 1.49, 3.43) with addition of comorbidities, corresponding to a %ERE of 21%. The hazard ratio was 1.98 (95% confidence interval: 1.29, 3.06) after addition of nutritional indicators corresponding to %ERE of 38%. Results stratified by age and gender followed similar patterns. CONCLUSION:: These results provide support for the assessment of handgrip strength in all maintenance hemodialysis patients for early identification of those who may require special care to improve nutritional status and survival.

A 3-day diary of dietary protein and calorie intake by serum phosphate concentration and binder use in hemodialysis patients.

INTRODUCTION: The use of phosphate binders to control hyperphosphatemia may allow diets less restricted in protein and calories for maintenance hemodialysis (MHD) patients. The study compared intakes of protein, calorie and phosphate among MHD patients with different serum phosphate concentrations, taking into account binder use. The hypothesis was that low serum phosphate would be associated with low intakes of protein and calories only in patients not on binders. METHODS: A cross-sectional study of 443 patients enrolled in the Prospective Study of the Prognosis of Chronic Hemodialysis Patients (PROHEMO) in Salvador, Brazil, with stratified sampling on serum phosphate: ≤3.0 (n = 41), 3.5-5.5 (n = 328) and ≥7.0 mg/dL (n = 74). A 3-day diet diary was used to determine dietary intakes. RESULTS: Approximately 49.0% confirmed binder use. Covariate-adjusted linear regression showed that associations between dietary intakes and serum phosphate were modified by the binder use. In patients not on binders, protein intake was >20% lower for serum phosphate ≤3.0 mg/dL compared to higher concentrations. Also in those not on binders, calorie intake was >30% lower for serum phosphate ≤3.0 mg/dL compared to ≥7.0 mg/dL. Differences in dietary intakes by serum phosphate were virtually absent in patients on binders. CONCLUSIONS: The results are consistent with the hypothesis that low serum phosphate is associated with low protein and calorie intake only among MHD patients not on binders. This study supports recommendations to prevent hyperphosphatemia in MHD patients by adequate combination of binder use and selection of foods restricted in phosphors but not severely restricted in protein and calories.

Associations of physical activity energy expenditure with nutritional-inflammatory markers in hemodialysis patients.

BACKGROUND: Sedentariness, high inflammation status and malnutrition are highly prevalent in end-stage kidney disease patients on maintenance hemodialysis (MHD). This study investigated associations of weekly physical activity energy expenditure (PAEE) with clinical and anthropometric markers of nutrition and inflammation. METHODS: The analysis was performed using baseline cross-sectional data of 640 patients enrolled in the prospective cohort "The Prospective Study of the Prognosis of Patients Treated Chronically by Hemodialysis" (PROHEMO) developed in Salvador, BA, Brazil. The long version of the International Physical Activity Questionnaire was used to determine a summary measure of PAEE, the metabolic equivalent of task (MET), taking into account physical activities related to occupation, recreation, travel, sports, and housework. PAEE was the predictor variable. To assess associations of PAEE with outcomes, the sex-age-specific median MET was used. The malnutrition-inflammation score (MIS) with range of 0 to 30 (higher is worse), conicity index as indicator of abdominal adiposity and C-reactive protein (CRP) were the nutritional-inflammatory outcomes. RESULTS: The mean age of the patients was 48.9 ± 13.8 y, 60.3% were males, 16.7% diabetic, 88.1% nonwhite. In multivariable logistic regression models with adjustments for sociodemographic variables and comorbidities, PAEE ≤median was associated with MIS ≥6 (odds ratio [OR] = 1.57; 95% confidence interval [CI] = 1.08, 2.29), conicity index ≥1.3 (OR = 1.52, 95% CI = 1.03, 2.23) and CRP >1.30 mg/dL (OR = 1.69, 95% CI = 1.08, 2.84). CONCLUSIONS: Greater physical activity assessed by PAEE was associated with indicators of better nutritional and inflammation status. These results indicate opportunities for improving outcomes in MHD patients by counseling and treatment intervention.