Insulin-like growth factor-I in patients on CAPD and hemodialysis: relationship to body weight and albumin level.

The relationship between insulin-like growth factor-I (IGF-I), body weight, and serum albumin was studied in 17 patients on continuous ambulatory peritoneal dialysis (CAPD) and 17 patients on hemodialysis. Patients were matched for gender, age (33-83 years), body mass index (16.7-36.1 kg/m2), hematocrit, concentrations of serum growth hormone, and duration of dialysis (1-210 months). Serum IGF-I concentration was measured by radioimmunoassay (Incstar) and albumin by a standard laboratory technique. CAPD patients had significantly lower serum albumin concentrations than hemodialysis patients, whereas IGF-I levels in the two groups were similar and did not differ from those in 18 normal subjects. We did not find significant positive correlations between IGF-I and serum albumin levels in CAPD or in hemodialysis patients. On the other hand, IGF-I showed a strong positive correlation with body weight (for the CAPD group r = 0.523; for both groups together r = 0.493). Both groups (CAPD and hemodialysis) and CAPD patients who weighted less than 60 kg (44%) had significantly lower serum IGF-I levels (113.5 +/- 10.2 and 108.8 +/- 15.7 micrograms/l +/- SEM, respectively) than patients who weighed 60-80 kg (38.3%; 181.2 +/- 20.9 and 196.6 +/- 27.2 micrograms/L +/- SEM, respectively) or above 80 kg (17.6%; 205.2 +/- 37.7 and 229.5 +/- 43.5; micrograms/L +/- SEM, respectively). It therefore appears that a low serum IGF-I level is a better indicator of malnutrition in CAPD and hemodialysis patients than low serum albumin.