To determine the influence of glycemic control improvement with intensive therapy on lipoprotein(a) [Lp(a)] concentrations in type 1 diabetic patients.
A total of 105 poorly controlled type 1 diabetic patients (60 men, 45 women) without diabetic complications participated in a longitudinal study performed in a tertiary referral center, to compare lipid, lipoprotein, and Lp(a) levels before and after 3 months of intensive therapy with multiple insulin doses. Lp(a) levels were measured by the Terumo method. Differences between the two periods were assessed by the paired t test and Wilcoxon's test.
After 3 months of intensive therapy, all patients exhibited improved glycemic control. HbA1c decreased from 8.9 ± 2.4 to 6.5 ± 1.6% (P < 0.0001), being ≤6% in 47% of patients. However, although a more favorable lipoprotein profile was obtained, no changes in Lp(a) concentrations were observed in the whole group of patients (16.7 ± 17.3 vs. 17.2 ± 17.7 mg/dl) or in patients with baseline Lp(a) levels above 30 mg/dl (47.1 ± 14.8 vs. 47.4 ± 18.9 mg/dl) or below 30 mg/dl (9.6 ± 7.3 vs. 10.2 ± 6.7 mg/dl). In addition, patients reaching HbA1c ≤6 or >6% presented similar Lp(a) levels (19.7 ± 18.0 vs. 15.0 ± 17.4 mg/dl), and changes in Lp(a) did not correlate with those observed in HbA1c.
These data demonstrate that the improvement of glycemic control does not influence plasma Lp(a) concentrations in type 1 diabetic patients independently of baseline Lp(a) levels and the degree of glycemic control.