Relationship between lipoprotein profile and urinary albumin excretion in type II diabetic patients with stable metabolic control

OBJECTIVE - To assess lipids and lipoprotein composition and the relationship between lipoprotein abnormalities and urinary albumin excretion (UAE) in select type II diabetic patients with stable metabolic control. RESEARCH DESIGN AND METHODS - Fifty-five type II diabetic patients and 55 healthy control subjects both with a body mass index < 30 kg/m2were studied. Patients were classified according to their level of UAE as normoalbuminuric (n = 37), microalbuminuric (n = 11), and macroalbuminuric (n = 7). In all cases, serum creatinine and albumin concentrations were in the normal range. RESULTS - Normoalbuminuric patients showed increased triglyceride (TG) contents in intermediate-density lipoprotein (IDL) (P < 0.01), low-density lipoprotein (LDL) (P < 0.001), and high-density lipoprotein (HDL) (P < 0.001) compared with control subjects. Lipoprotein concentration in microalbuminuric patients did not differ from that of normoalbuminuric patients. On the other hand, patients with macroalbuminuria showed a significant increase in IDL cholesterol (P < 0.01) and IDL (P < 0.01), LDL (P < 0.05), and HDL TGs (P < 0.01) compared with the other groups. Diabetic patients with nephropathy, both microalbuminuric and macroalbuminuric, tended to have higher mean lipoprotein(a) (Lp[a]) concentrations than normoalbuminuric patients and control subjects. A strongly positive correlation was observed between UAE and serum TGs (r = 0.56) and very-low-density lipoprotein (r = 0.55), IDL (r = 0.52), LDL (r = 0.54), and HDL TGs (r = 0.52). CONCLUSIONS - Lipoprotein alterations observed in diabetic patients, specifically IDL abnormalities and a tendency toward high Lp(a) levels, which are more marked in those with increased UAE, may contribute to the excess of cardiovascular disease in type I diabetic patients, particularly those with nephropathy.