IL-6 Levels, Nutritional Status, and Mortality in Prevalent Hemodialysis Patients

Abstract

SummaryBackground 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 Ϯ 10.6 years, were studied after exclusion of patients with BMI Ͻ 20 kg/m 2 and/or serum albumin Ͻ35 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 Ϯ 0.44 pg/ml per 2 yrs; P ϭ 0.001) and adjusted models (linear estimate: 2.35 Ϯ 0.57 pg/ml per 2 yrs; P ϭ 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 ϭ 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. ConclusionsOur 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.

Clinical Predictors of Decline in Nutritional Parameters over Time in ESRD

“…The latter may have biased their findings (i.e., stable CRP levels over time). Increasing IL-6 levels over time are in accordance with data from two HEMO study centers as well as a recent Israeli study (8,21). The inverse relationships between changes in CRP and IL-6 with albumin are in accordance with other studies, reflecting a negative influence of inflammation on albumin synthesis (12,13).…”

“…In another study of 64 prevalent hemodialysis patients, albumin improved and body weight and C-reactive protein (CRP) remained stable during 36 months of followup (7). IL-6 increased over time in a study of 85 prevalent hemodialysis patients (8). Other studies with multiple measurements of CRP in ESRD patients focused on predictive power (9)(10)(11).…”

Comparison Analysis of Nutritional Scores for Serial Monitoring of Nutritional Status in Hemodialysis Patients

“…Of interest, the observations that both MIS and GNRI change with time are strongly associated with longitudinal changes of IL-6 levels in our cohort. Because IL-6 is the best indicator of an inflammatory response (26), this in turn represents a powerful predictor of mortality in the maintenance hemodialysis population (27)(28)(29) and this finding can be considered as an additional strength for both scores.…”

Serum Obestatin: A Biomarker of Cardiovascular and All-Cause Mortality in Hemodialysis Patients

“…MHD patients with higher IL-6 and lower obestatin concentrations presented the highest mortality risk. The role of chronic inflammation, as evidenced by the presence of higher IL-6 levels, in the low survival rate in MHD population has been widely documented [24]. There is very scant information in the literature about the relationship between the obestatin and IL-6.…”