LACK OF CHANGE OF LIPOPROTEIN(A) LEVELS BY THE OPTIMIZATION OF GLYCEMIC CONTROL WITH INSULIN THERAPY IN NIDDM PATIENTS

OBJECTIVE - To evaluate the effect of glycemic control improvement wit h insulin therapy on lipoprotein(a) [Lp(a)] levels in patients with NI DDM. RESEARCH DESIGN AND METHODS - We performed a longitudinal study i n a tertiary referral center to compare lipid and Lp(a) levels before and after 3 months of insulin therapy in 60 poorly controlled NIDDM pa tients (32 men, 28 women). Patients previously treated with oral hypog lycemic agents (n = 50) received one to two insulin doses, and those p reviously treated with insulin (n = 10) received multiple insulin dose s. Lp(a) levels were measured by the Terumo method. Differences betwee n the two periods were assessed by the paired t test and Wilcoxon's te st. RESULTS - After 3 months of insulin therapy HbA(1c) decreased from 9.6 +/- 1.9 to 6.0 +/- 1.4% (P < 0.0005) in all patients and from 9.1 +/- 2.1 to 6.1 +/- 2.9% (P < 0.05) in patients under multiple insulin doses, being less than or equal to 6.0% in 59% of patients. Total tri glyceride and VLDL cholesterol levels decreased (P < 0.01) and HDL cho lesterol increased significantly (P < 0.0005). However, no changes in Lp(a) levels were observed in all patients (25.3 +/- 25.0 vs 25.7 +/- 27.2% mg/dl) and in patients with baseline Lp(a) levels above (63.5 +/ - 15.5 vs. 65.1 +/- 23.1 mg/dl) or below 30 mg/dl (11.5 +/- 7.5 vs. 11 .5 +/- 7.3 mg/dl). In addition, patients reaching HbA(1c) levels less than or equal to 6.0% or >6.0% presented similar Lp(a) levels (26.0 +/ - 29.1 vs 25.3 +/- 25.0 mg/dl). Moreover, no correlations were observe d between changes in Lp(a) levels and in the glycemic control paramete rs. CONCLUSIONS - This study shows that the improvement of glycemic co ntrol by insulin therapy does not influence plasma Lp(a) levels, measu red by the Terumo method, in NIDDM patients, independently of baseline values and the degree of glycemic control reached.