APOLIPOPROTEIN (A) LEVELS AND PHENOTYPES IN NIDDM-1 PATIENTS WITH MICROALBUMINURIA AND ALBUMINURIA

This study was conducted to determine whether circulating levels of li poprotein (a), an independent risk factor of macrovascular disease, ar e increased in non-insulin-dependent diabetes mellitus (NIDDM) patient s with microalbuminuria who have an increased risk of cardiovascular m ortality. Apolipoprotein (a) [apo(a)] levels and phenotypes, and other circulating lipid levels were determined in 227 Chinese NIDDM patient s with varying stages of diabetic nephropathy. None was on lipid-lower ing therapy. Apo(a) levels in normoalbuminuric (geometric mean 166 U/L ; 95% confidence intervals 137, 200; n = 10.5) and microalbuminuric pa tients (162; 132, 209; n = 77) were similar to values in controls (166 ; 143, 193, n = 168). Albuminuric patients, however, had higher apo(a) levels than both normoalbuminuric patients and controls (242; 184, 31 7; n = 45; P < 0.05). The overall size range of the apo(a) phenotypes and the frequency of having at least one small isoform, i.e. < 700 kDa , were similar among the four groups of subjects. A positive correlati on was found between log apo(a) and log plasma creatinine levels (P < 0.01). Compared to normoalbuminuric patients, both microalbuminuric an d albuminuric patients were older (P < 0.01) and had higher HbAlc (P < 0.01), greater BMI (P < 0.05) and longer disease duration (P < 0.05) compared to normoalbuminuric patients. Nevertheless, using multiple li near regression analysis, it was found that the presence of nephropath y conferred an independent influence on increasing total cholesterol ( P < 0.001), triglyceride (P < 0.001) and apoB (P < 0.01), and decreasi ng HDL cholesterol (P < 0.05) levels even when only the normoalbuminur ic and microalbuminuric groups were analysed. The prevalence of macrov ascular disease was significantly increased in microalbuminuric and al buminuric patients (45.1 and 48.7% respectively vs 20.2% in normoalbum inuric patients, P < 0.01). It is concluded that circulating apo(a) le vels were not increased in Chinese NIDDM patients with microalbuminuri a. However, atherogenic changes in other lipid and lipoprotein levels may contribute to an increased risk of macrovascular disease in these patients.