IL-6 levels, nutritional status, and mortality in prevalent hemodialysis patients.

BACKGROUND AND OBJECTIVES: The influence of serum IL-6 levels on nutritional status in chronic hemodialysis (HD) patients remains to be elucidated. The present report describes a prospective longitudinal study of IL-6 levels and nutritional parameters to determine whether high IL-6 levels are independently associated with nutritional status over time in a cohort of prevalent hemodialysis patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: 85 clinically stable hemodialysis patients (37.6% women), with a mean age of 66.5 ± 10.6 years, were studied after exclusion of patients with BMI < 20 kg/m(2) and/or serum albumin <35 g/L. IL-6, dietary energy and protein intake, and biochemical markers of nutrition and body composition (anthropometry and bioimpedance analysis) were measured at baseline and at 6, 12, 18, and 24 months following enrollment. Observation of this cohort was continued over 2 additional years. RESULTS: IL-6 levels increased with time in both unadjusted (linear estimate: 2.57 ± 0.44 pg/ml per 2 yrs; P = 0.001) and adjusted models (linear estimate: 2.35 ± 0.57 pg/ml per 2 yrs; P = 0.049). Significant reductions of daily energy intake, laboratory markers (albumin, transferrin, cholesterol, creatinine), and body composition (fat mass) with higher IL-6 levels were observed over the duration of the longitudinal observation period. However, none of the studied parameters were associated with changes in IL-6 levels over time (IL-6-by-time interactions were NS). Furthermore, cumulative incidences of survival were correlated with the baseline serum IL-6 levels (P = 0.004 by log-rank test). Finally, for each pg/ml increase in IL-6 level, the hazard ratio for death from all causes was 1.06 (95% CI 1.01 to 1.10) after adjustment for demographic and clinical parameters. CONCLUSIONS: Our results suggest that higher serum IL-6 levels are associated with all-cause mortality without additional changes in clinical and laboratory markers of nutritional status in clinically stable HD patients.

Longitudinal study of leptin levels in chronic hemodialysis patients.

BACKGROUND: The influence of serum leptin levels on nutritional status and survival in chronic hemodialysis patients remained to be elucidated. We conducted a prospective longitudinal study of leptin levels and nutritional parameters to determine whether changes of serum leptin levels modify nutritional status and survival in a cohort of prevalent hemodialysis patients. METHODS: Leptin, dietary energy and protein intake, biochemical markers of nutrition and body composition (anthropometry and bioimpedance analysis) were measured at baseline and at 6, 12, 18 and 24 months following enrollment, in 101 prevalent hemodialysis patients (37% women) with a mean age of 64.6 ± 11.5 years. Observation of this cohort was continued over 2 additional years. Changes in repeated measures were evaluated, with adjustment for baseline differences in demographic and clinical parameters. RESULTS: Significant reduction of leptin levels with time were observed (linear estimate: -2.5010 ± 0.57 ng/ml/2 y; p < 0.001) with a more rapid decline in leptin levels in the highest leptin tertile in both unadjusted (p = 0.007) and fully adjusted (p = 0.047) models. A significant reduction in body composition parameters over time was observed, but was not influenced by leptin (leptin-by-time interactions were not significant). No significant associations were noted between leptin levels and changes in dietary protein or energy intake, or laboratory nutritional markers. Finally, cumulative incidences of survival were unaffected by the baseline serum leptin levels. CONCLUSIONS: Thus leptin levels reflect fat mass depots, rather than independently contributing to uremic anorexia or modifying nutritional status and/or survival in chronic hemodialysis patients. The importance of such information is high if leptin is contemplated as a potential therapeutic target in hemodialysis patients.

Objective Score of Nutrition on Dialysis (OSND) as an alternative for the malnutrition-inflammation score in assessment of nutritional risk of haemodialysis patients.

BACKGROUND: Evaluation of nutritional risk, one of the strongest predictors of morbidity and mortality in maintenance haemodialysis (HD) patients, is a difficult process especially in patients with compounding conditions that prevent subjective assessment by subjective global assessment or malnutrition-inflammation score (MIS). METHODS: In this study, we developed and characterized a score for the assessment of nutritional status in dialysis patients based solely on objectively measurable criteria. Our prospective observational cohort included 81 prevalent HD patients (53 men and 28 women) with a mean age of 64.3 +/- 11.9 years. The study period encompassed 26.9 +/- 14.3 months. The quantitative and comprehensive scoring system, named Objective Score of Nutrition on Dialysis (OSND), was calculated by combining anthropometric measurements (the change in end-dialysis dry weight in the past 3-6 months, body mass index, skinfold thickness and mid-arm circumference) with three laboratory tests: albumin, transferrin and cholesterol levels. The sum of all seven components of OSND results in a score from 5 (severely malnourished) to 32 (normal). We compared our OSND system with the accepted MIS and phase angle (PA) measurements derived by bioelectric impedance analysis. RESULTS: The OSND correlated significantly with hospitalization days (r = -0.334; P = 0.002) and frequency of hospitalization (r = -0.373; P = 0.001), as well as with lean body mass and fat mass, MIS, PA and interleukin-6 levels. The Cox proportional hazard-calculated relative risk for death for each five-unit decrease in the OSND was 2.2 (95% CI, 1.3 to 3.8; P = 0.003) comparable with the predictions provided by MIS [for each five-unit increase in MIS, hazard ratio (HR) was 1.8 with 95% CI, 1.2 to 2.8; P = 0.007] and PA (for each 1-unit decrease in PA, HR was 2.9 with 95% CI, 1.5 to 5.6; P = 0.001). CONCLUSIONS: The OSND thus provides a comprehensive scoring system with significant associations with prospective hospitalization and mortality in chronic HD patients as well as measures of nutrition and inflammation.

Nutritional and inflammatory status of hemodialysis patients in relation to their body mass index.

OBJECTIVE: The study tested whether obese hemodialysis (HD) patients have a better nutritional and inflammatory state than those with overweight or normal body mass index (BMI). DESIGN: This was a single-center, cross-sectional study. SETTING AND PATIENTS: Ninety-six stable HD patients from a local HD unit were divided into 3 groups according to BMI (normal, overweight, and obese). MAIN OUTCOME MEASURES: Anthropometry, body composition by multifrequency bioelectrical impedance analysis, biochemical nutritional markers, as well as interleukins (IL-1, IL-6, and IL-10), tumor necrosis factor, leptin, and soluble leptin receptor (sOB-R) were measured. RESULTS: Serum creatinine was significantly elevated in the highest BMI category. Albumin and transferrin were significantly elevated in higher BMI groups after adjustment for age, sex, and diabetes status. The higher BMI group had greater lean body mass (P = .001) and fat mass (P = .0001), higher phase angle (PA), and lower extracellular mass-to-body-cell-mass ratio (ECM/BCM) (P < .05). Inflammatory cytokine levels were not different in the 3 BMI groups. In parallel with increasing BMI, a gradual increase in serum leptin and a trend for decreasing sOB-R were detected (P = .0001 and P = .055, respectively). Both PA (r = 0.295, P = .008) and ECM/BCM (r = -0.345, P = .002) significantly correlated with serum leptin concentration. According to a multiple linear regression analysis, with PA as the dependent variable, age (beta = 0.274, P = .008), creatinine (beta = 0.355, P = .001), and log sOB-R/leptin ratio (beta = -0.465, P = .008) were significant independent predictors of PA. CONCLUSION: HD patients with elevated BMI demonstrate better nutritional status compared to normal BMI or overweight patients, whereas the severity of inflammation is not related to BMI in HD patients.