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.

Updates on medical management of hyperkalemia.

PURPOSE OF REVIEW: Hyperkalemia is a potentially fatal electrolyte disorder, more commonly present when the potassium excretion capacity is imparied. Hyperkalemia can lead to adverse outcomes, especially due to severe cardiac arrhythmias. It can also impair the cardiovascular effects of renin-angiotensin-aldosterone system inhibitors (RAASis) and potassium rich diets, as hyperkalemia frequently leads to their discontinuation. RECENT FINDINGS: Potassium is a predictor of mortality and should be monitored closely for patients who are at risk for hyperkalemia. Acute hyperkalemia protocols have been revised and updated. Randomized trials have shown that the new anti-hyperkalemic agents (patiromer and zirconium cyclosilicate) are effective hyperkalemia treatment options. The use of anti-hyperkalemic agents may allow for a less restrictive potassium diet and lower RAASi discontinuation rates. SUMMARY: Hyperkalemia should be monitored closely for high-risk patients, as it is associated with adverse outcomes. New therapies have demonstrated effective control, offering hope for potential use in patients that would benefit from diet or medications associated with an increase in serum potassium, indicating that the use of hyperkalemic agents can be associated with better outcomes.

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.

Estimation of glomerular filtration rate from serum creatinine and cystatin C in octogenarians and nonagenarians.

BACKGROUND: Equations to estimate GFR have not been well validated in the elderly and may misclassify persons with chronic kidney disease (CKD). We measured GFR and compared the performance of the Modification of Diet in Renal Disease (MDRD), the Chronic Kidney Disease-Epidemiology Collaboration (CKD-Epi) and the Berlin Initiative Study (BIS) equations based on creatinine and/or cystatin C in octogenarians and nonagenarians. METHODS: Using cross-sectional analysis we assessed 95 very elderly persons (mean 85 years) living in the community. GFR was measured by iohexol (mGFR) and compared with estimates using six equations: MDRD, CKD-Epi_creatinine, CKD-Epi_cystatin, CKD-Epi_creatinine-cystatin, BIS_creatinine and BIS_creatinine-cystatin. RESULTS: Mean mGFR was 55 (range,19-86) ml/min/1.73 m(2). Bias was smaller with the CKD-Epi_creatinine-cystatin and the CKD-Epi_creatinine equations (-4.0 and 1.7 ml/min/1.73 m(2)). Accuracy (percentage of estimates within 30% of mGFR) was greater with the CKD-Epi_creatinine-cystatin, BIS_creatinine-cystatin and BIS_creatinine equations (85%, 83% and 80%, respectively). Among the creatinine-based equations, the BIS_creatinine had the greatest accuracy at mGFR < 60 ml/min/1.73 m(2) and the CKD-Epi_creatinine was superior at higher GFRs (79% and 90%, respectively). The CKD-Epi_creatinine-cystatin, BIS_creatinine-cystatin and CKD-Epi_cystatin equations yielded the greatest areas under the receiver operating characteristic curve at GFR threshold = 60 ml/min/1.73 m 2 (0.88, 0.88 and 0.87, respectively). In participants classified based on the BIS_creatinine, CKD-Epi_cystatin, or BIS_creatinine-cystatin equations, the CKD-Epi_creatinine-cystatin equation tended to improve CKD classification (net reclassification index: 12.7%, p = 0.18; 6.7%, p = 0.38; and 15.9%; p = 0.08, respectively). CONCLUSIONS: GFR-estimating equations CKD-Epi_creatinine-cystatin and BIS_creatinine-cystatin showed better accuracy than other equations using creatinine or cystatin C alone in very elderly persons. The CKD-Epi_creatinine-cystatin equation appears to be advantageous in CKD classification. If cystatin C is not available, both the BIS_cr equation and the CKD-Epi_cr equation could be used, although at mGFR < 60 ml/min/1.73 m(2), the BIS_cr equation seems to be the best alternative.