Relationship Between Serum Leptin Levels and Body Composition and Markers of Malnutrition in Nondiabetic Patients on Peritoneal Dialysis or Hemodialysis

Leptin is a protein hormone secreted by adipocytes, regulating body fat and food intake. It has been reported that serum leptin levels are high in patients with chronic renal failure, and this fact has been associated with malnutrition and body composition changes in patients on hemodialysis. This present study investigated the relationship between plasma leptin concentrations and body composition and markers of malnutrition in nondiabetic patients diagnosed with end-stage chronic renal failure, treated with continuous ambulatory peritoneal dialysis (CAPD) or hemodialysis (HD). A total of 152 HD and 32 CAPD patients were enrolled into the study. The body compositions of the patients were established by utilizing a Body Composition Analyzer. Triceps skinfold thickness (TSFT) was measured by using a Harpenden Skinfold Caliper. Serum leptin level was detected by radioimmunoassay in ng/mL through employing a DPC Gambyt-CR gamma counter. Standard laboratory methods were used for measuring the remaining parameters (total protein, albumin, blood urea nitrogen, creatinine, hemoglobin, hematocrit, high-sensitivity C-reactive protein [hsCRP]). No significant difference was observed between the HD and CAPD groups regarding leptin levels. Leptin levels of female patients in both groups were markedly higher when compared with those of men ( p = 0.001). Plasma leptin levels in total, as well as for both male and female HD and CAPD patients, significantly correlated positively with age, percent fat, fat mass, body mass index and TSFT ( p = 0.001). Serum leptin levels were not found to be correlated with length of time on dialysis, lean body mass, total body water, hsCRP, total protein and albumin levels ( p > 0.05). The data obtained in this study indicated that serum leptin levels could be instrumental markers in establishing body fat ratio, as well as in determining metabolic and nutritional factors in patients with chronic renal failure.