Association of metabolic changes with mortality of patients treated by peritoneal dialysis or hemodialysis

U-Shaped Association between Waist-to-Hip Ratio and All-Cause Mortality in Stage 3-5 Chronic Kidney Disease Patients with Body Mass Index Paradox

The obesity paradox, referring to the association of high body mass index (BMI) with low all-cause mortality risk, is found in patients with chronic kidney disease (CKD). Central obesity is associated with metabolic syndrome and may have better prognostic value than BMI for all-cause mortality. Whether central obesity is associated with all-cause mortality in cases of obesity paradox in CKD patients remains unknown. We included 3262 patients with stage 3–5 CKD, grouped into five quintiles (Q1–5) by waist-to-hip ratio (WHR). Low WHR and BMI were associated with malnutrition and inflammation. In Cox regression, high BMI was not associated with all-cause mortality, but BMI < 22.5 kg/m² increased the mortality risk. A U-shaped association between central obesity and all-cause mortality was found: WHR Q1, Q4, and Q5 had higher risk for all-cause mortality. The hazard ratio (95% confidence interval) of WHR Q5 and Q1 for all-cause mortality was 1.39 (1.03–1.87) and 1.53 (1.13–2.05) in male and 1.42 (1.02–1.99) and 1.28 (0.88–1.85) in female, respectively. Waist-to-height ratio and conicity index showed similar results. Low WHR or low BMI and high WHR, but not high BMI, are associated with all-cause mortality in advanced CKD.

Obesity and the risk of cardiovascular and all-cause mortality in chronic kidney disease: a systematic review and meta-analysis

Background

Obesity is a risk factor for cardiovascular disease and death in people without chronic kidney disease (CKD), but the effect of obesity in people with CKD is uncertain.

Methods

Medline and Embase (from inception to January 2015) were searched for cohort studies measuring obesity by body mass index (BMI), waist:hip ratio (WHR) and/or waist circumference (WC) and all-cause and cardiovascular mortality or events in patients with any stage of CKD. Data were summarized using random effects models. Meta-regression was conducted to assess sources of heterogeneity.

Results

Of 4065 potentially eligible citations, 165 studies ( n = 1 534 845 participants) were analyzed. In studies that found a nonlinear relationship, underweight people with CKD (3-5) on hemodialysis experienced an increased risk of death compared with those with normal weight. In transplant recipients, excess risk was observed at levels of morbid obesity (>35 kg/m 2 ). Of studies that found the relationship to be linear, a 1 kg/m 2 increase in BMI was associated with a 3 and 4% reduction in all-cause and cardiovascular mortality in patients on hemodialysis, respectively {adjusted hazard ratio [HR] 0.97 [95% confidence interval (CI) 0.96-0.98] and adjusted HR 0.96 (95% CI 0.92-1.00)}. In CKD Stages 3-5, for every 1 kg/m 2 increase in BMI there was a 1% reduction in all-cause mortality [HR 0.99 (95% CI 0.0.97-1.00)]. There was no apparent association between obesity and mortality in transplanted patients or those on peritoneal dialysis. Sparse data for WHR and WC did not allow further analyses.

Conclusions

Being obese may be protective for all-cause mortality in the predialysis and hemodialysis populations, while being underweight suggests increased risk, but not in transplant recipients.

Abdominal Obesity and Mortality in Continuous Ambulatory Peritoneal Dialysis Patients

Background

The relationship between abdominal obesity (AO) and mortality in peritoneal dialysis (PD) patients is controversial.

Methods

The prevalence of AO in 84 PD patients was assessed in a cross-section manner and followed up for 9 years at a single center. AO was defined as a waist circumference (WC) of more than 90 cm in males or more than 80 cm in females. The patients were classified as either with AO(AO group) or without AO(nAO group).

Results

The AO group was older, contained more diabetics, more females, and had higher Charlson comorbidity index (aCCI) scores, BMI, and triglyceride and lower serum creatinine than the non-AO subjects. The follow-up duration was 53.2±34.4 months. At the end of the follow-up, eighteen patients (21.4%) were dead; 9 died of cardiovascular causes. The five year survival rate was 40.8%. Kaplan-Meier analysis revealed that both all-cause and cardiovascular-cause mortalities were similar in the AO and nAO groups. Multivariate analysis revealed the presence of AO not to be an independent risk factor of all-cause and cardiovascular-cause mortality.

Conclusion

AO itself might not be a risk factor for mortality in PD patients. Nevertheless, further prospective studies with a large number of patients will be needed to prove this.

Residual urinary output in high body mass index individuals on chronic hemodialysis: A disregarded life vest?

AIM: To assess residual diuresis and diverse variables according to body mass index (BMI).

METHODS: Cross-sectional study (n = 57), with 3 groups. Group A: BMI < 25, n = 22; Group B: BMI 25-30, n = 15; Group C: BMI > 30, n = 20. Diuresis, hematocrit, albumin, C-reactive protein, Malnutrition inflammatory score, Pro-BNP, Troponin T, leptin and insulin levels are expressed as median and ranges (r).

RESULTS: Albumin (g/dL): GA vs GC, 3.70 (r2.20-4.90) vs 3.85 (r3.40-4.90), P = 0.02. Diuresis (mL/d): GA 690 (r0-1780); GB 660 (r60-1800); GC 840 (r40-2840). Diuresis GA vs GC, P = 0.01. Leptin (ng/mL): GA vs GC, 3.81 (r0.78-69.60) vs GC, 32.80 (r0.78-124.50), P < 0.001. Insulin (µU/mL): GA vs GB, 7 (r2-44) vs 11.50 (r4-38), P = 0.02; GA vs GC, 7 (r2-44) vs 19.5 (r5-155), P = 0.0001. Troponin T and Pro-BNP levels were not different. Significant correlations: GC, Insulin-UF: ρ = 0.53; P = 0.03; TroponinT-diuresis: ρ = -0.48, P < 0.05; Pro-BNP-diuresis: ρ = -0.39, P < 0.01; Troponin T-ProBNP: ρ = 0.77, P < 0.0001; albumin-Troponin T: ρ = -0.66, P < 0.0001; albumin-ProBNP: ρ = -0.44, P < 0.05.

CONCLUSION: High BMI associated positively with higher diuresis and albuminemia, and negatively with TropT and Pro-BNP. High BMI-associated better survival may be explained by better urinary output, lowering cardiovascular stress.

Dialysis patients with the metabolic syndrome need less recombinant human erythropoietin for similar hemoglobin levels

INTRODUCTION

The metabolic syndrome (MS) components, such as dyslipidemia, prothrombotic status, and increased blood pressure, are risk factors for patients with renal disease. Visceral fat mass is closely related to the MS and atherosclerosis. We investigated the effects of body compositions and MS on anemia parameters and recombinant human erythropoietin (rHuEPO) requirements in maintenance hemodialysis patients.

METHODS

Body composition (body mass index and bioimpedance analysis) and laboratory data were obtained from 110 dialysis patients. The MS was identified according to ATP-III criteria. Anemia parameters, hemoglobin (Hgb), albumin, C-reactive protein (CRP), calcium, phosphorus, parathormone levels, and rHuEPO requirements over the last 6 months were retrospectively analyzed.

RESULTS

Patients with the MS seem to reach target Hgb levels more frequently (10-12 g/dL; 66.3% vs 84.8%; P = .03) without any difference in total intravenous iron therapy dosage. MS patients also required lower rHuEPO for reaching similar Hgb levels compared with patients without MS (2679.3 ± 1936.1 vs 3702.5 ± 2213.0 U/kg/6 mo; P = .02). There were no differences in serum CRP, albumin, or Hgb levels between the 2 groups (P > .05). We observed that patients with MS had significantly higher fat mass and visceral fat ratio, but similar muscle mass values compared with no-MS counterparts (P = .0001 and .001, respectively). However, when we compared the ratios of these parameters we observed a significant reduction in muscle ratios and a significant increase in fat ratios of MS patients (P = .0001).

CONCLUSION

Our results indicate that MS might be an advantage for reaching higher Hgb levels with lower rHuEPO dosages. The possible reason for this might be the good nutritional state and increased fat mass of patients with MS.

Association of inflammatory biomarkers with metabolic syndrome in hemodialysis patients

The relative importance of inflammatory markers in relation with metabolic syndrome (MeS) in hemodialysis (HD) patients is uncertain. This study investigated the association between MeS and high-sensitive C-reactive protein (hsCRP), hallmark of inflammation, and other inflammatory-related biomarkers. The study included 153 patients who were dialyzed at least for the last 3 months. The serum level of hsCRP was assessed by high-sensitive Enzyme-linked immunosorbent assay (ELISA). MeS was defined using the modified National Cholesterol Education Program Adult Treatment Panel III (ATP-III). Ninety-one HD patients (59.5%) were diagnosed as having MeS. Lower level of high-density lipoprotein-cholesterol (HDL-C) was the most prevalent MeS component (85.6%). The serum level of hsCRP in these patients was significantly higher than that in HD patients without MeS (2.3 ± 1.7 vs. 1.7 ± 1.6 mg/dL, p = 0.03). A significant linear increase in the hsCRP levels was found according to the number of MeS components (β = 0.09, p = 0.022). The study concluded that increasing inflammatory biomarkers, especially hsCRP, is associated with MeS in HD patients.