Association of the serum leptin concentration with weight loss in chronic hemodialysis patients

Circulating leptin, which is partly cleared by the kidney, has been reporte d to increase with chronic renal failure and thus may play a role in the we ight loss of patients with chronic renal failure. We investigated the assoc iation of body weight loss with the serum leptin concentration in Japanese hemodialysis patients. The relationship between serum leptin and the body m ass index (BMI) or body fat mass was compared among 181 patients undergoing hemodialysis and 185 control subjects. There was no difference in the seru m leptin concentration between the hemodialysis patients (HD) and controls (C) for either the men (3.9 +/- 0.2 ng/mL for HD, n=117; 3.9 +/- 0.3 ng/mL for C, n=89; NS) or women (8.9 +/- 1.2 ng/mL for HD, n=64; 7.4 +/- 0.5 ng/m L for C, n= 96; NS), whereas BMI at the hemodialysis patients was significa ntly lower than that of the controls for both the men (20.1 +/- 0.2 kg/m(2) for HD, 22.4 +/- 0.3 kg/m(2) for C, P < 0.001) and women (19.2 +/- 0.3 kg/ m(2) for HD, 22.0 +/- 0.4 kg/m(2) for C, P < 0.001). The serum leptin/body fat mass ratio was significantly correlated with the weight change of the p atients during a follow-up evaluation period of 17 months (r = -0.37, P < 0 .05 for men, n=27 and r = -0.53, P < 0.005 for women, n = 28), indicating t he possibility that a relatively high level of serum leptin had induced wei ght loss in the hemodialysis patients. The serum leptin/body fat mass ratio also showed a significant inverse correlation with the duration of hemodia lysis (r = -0.31, P < 0.05 for men and r = -0.49, P < 0.05 for women). A mu ltiple regression analysis indicated that the body fat mass was significant ly correlated with serum leptin concentration, whereas the fat distribution did not have any relationship with leptin. These data indicate that a high level of serum leptin relative to the body fat mass might be associated wi th weight loss in long-term hemodialysis patients. The serum leptin level r elative to the body fat mass also seems to have been affected by the durati on of hemodialysis. (C) 1999 by the National Kidney Foundation, Inc.