The effect of insulin delivery route on lipoproteins in type I diabetic patients on CAPD.
OBJECTIVE: To evaluate the influence of subcutaneous and intraperitoneal (i.p.) insulin on plasma lipoproteins in type I diabetic (IDDM) patients with end-stage renal failure (ESRD) treated with continuous ambulatory peritoneal dialysis (CAPD). DESIGN: A before-after trial. SETTING: University hospital outpatient care. PARTICIPANTS: Eleven IDDM patients with stabilized peritoneal dialysis, age 42.9 +/- 2.9 (SEM) years and duration of diabetes 31.4 +/- 3.4 years. INTERVENTION: Two treatment periods during stabilized CAPD. All patients were first treated with subcutaneous and then with i.p. insulin. The studies were performed after a median time of 3 months on each treatment. MAIN OUTCOME MEASURES: Plasma lipids; apoproteins (Apo) A-I, A-II, and B; high-density lipoprotein (HDL) subfractions; glycemic status; and uremic status. RESULTS: After changing from subcutaneous insulin to i.p. insulin, plasma HDL cholesterol decreased (from 1.29 +/- 0.13 mmol/L to 0.96 +/- 0.06 mmol/L, p < 0.05), and the low density to high density lipoprotein (LDL/HDL) cholesterol ratio increased (p < 0.05). The HDL cholesterol decreased in both HDL2 and HDL3 fractions, but significantly so only in HDL3 (p < 0.01). ApoA-I (p < 0.05) decreased while the ApoB/ApoA-I ratio (p < 0.01) and the ApoA-I/HDL-cholesterol ratio (p < 0.01) increased during i.p. insulin therapy. Intraperitoneal insulin resulted in significantly better glycemic control than subcutaneous insulin (p < 0.01). CONCLUSIONS: In diabetic patients on CAPD therapy, i.p. insulin, although inducing better glycemic control than subcutaneous insulin, was associated with lowered plasma HDL cholesterol and ApoA-I levels. The atherogenic potential is probably less than expected as the relative particle size of HDL remained unchanged.