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.
Fifty-five type II diabetic patients and 55 healthy control subjects both with a body mass index <30 kg/m2 were 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.
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).
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 II diabetic patients, particularly those with nephropathy.