Hyperleptinemia in patients with end-stage renal disease undergoing continuous ambulatory peritoneal dialysis

To determine whether the increased plasma leptin levels reported in hemodialyzed patients is a feature of end-stage renal disease or an artifact of hemodialysis, we studied plasma levels in patients treated exclusively by continuous ambulatory peritoneal dialysis (CAPD).

Prospective comparison of end points in CAPD patients and matched healthy subjects.

Tertiary care institutional dialysis center.

Fifty-six healthy subjects, age 50.8 +/- 2.3 years, body mass index (BMI) 27.7 +/- 1.3 kg/m2, recruited through public announcement, and 36 patients with end-stage renal disease, age 51.0 +/- 2.4 yr, BMI 28.2 +/- 1.3 kg/m2, enrolled in a CAPD treatment program.

Four exchanges of CAPD per day, using 2.0, 2.5, or 3.0 L of dialysate over a period of 1 - 96 months (median 22 mth).

The primary outcome measure was plasma leptin concentration. Secondary measures included plasma glucose, insulin, C-peptide, and cortisol concentrations; and residual renal function and dialysis adequacy (Kt/V).

Plasma leptin levels in CAPD patients were 27.1 - 490 ng/mL (women) and 1.3 - 355 ng/mL (men); the levels in healthy subjects were 2.0 - 84.7 ng/mL (women) and 1.8 - 55.4 ng/mL (men). The mean leptin levels were 5-fold higher among CAPD-treated men than control men (49.9 +/- 18.4 vs 9.8 +/- 2.5 ng/mL, p < 0.001) and 7.5-fold higher among CAPD-treated women than control women (220 +/- 28.1 vs 29.3 +/- 3.7 ng/mL, p < 0.0001). Female gender and BMI were the strongest predictors of hyperleptinemia in CAPD patients.

These results indicate that hyperleptinemia is a feature of terminal renal failure, not an artifact of hemodialysis.