Low Serum Leptin Predicts Mortality in Patients with Chronic Kidney Disease Stage 5*

Objective: Leptin, secreted from adipose tissue, regulates food intake, energy expenditure, and immune function. It is unknown whether leptin predicts mortality in patients with chronic kidney disease stage 5 on hemodialysis therapy. Research Methods and Procedures: We performed a prospective cohort study of 71 patients with chronic kidney disease stage 5 in an outpatient hemodialysis center. Subjects were recruited in June 1998 and followed for 83 months. Survival was compared by the Kaplan-Meier method. Results: After 83 months of follow-up, 48 patients (68%) had died. Serum leptin concentrations at study entry were lower among all deceased patients compared with those patients who survived (5.2 ± 9.0 μg/L; n = 48; vs. 7.7 ± 7.8 μg/L; n = 23; p = 0.005). Baseline serum leptin concentrations were significantly lower in patients who died from cardiovascular diseases (4.7 ± 9.4 μg/L, n = 32) or infections (4.0 ± 2.7 μg/L; n = 10; each p < 0.05), but not cancer (9.4 ± 7.9 μg/L; n = 6), than in survivors (7.7 ± 7.8 μg/L; n = 23; p = 0.003). The relative risk for mortality in patients with serum leptin concentrations below the median (