Objective: To investigate the association of the cardiovascular risk factor lipoprotein (Lp)(a) and vascular complications in patients with type 1 diabetes.
Research design and methods: Patients with type 1 diabetes receiving regular care were recruited in this observational cross-sectional study and divided into four groups according to their Lp(a) levels in nmol/L (very low <10, low 10-30, intermediate 30-120, high >120). Prevalence of vascular complications was compared between the groups. In addition, the association between metabolic control, measured as HbA1c, and Lp(a) was studied.
Results: The patients (n = 1,860) had a median age of 48 years, diabetes duration of 25 years, and HbA1c of 7.8% (61 mmol/mol). The median Lp(a) was 19 (interquartile range 10-71) nmol/L. No significant differences between men and women were observed, but Lp(a) levels increased with increasing age. Patients in the high Lp(a) group had higher prevalence of complications than patients in the very low Lp(a) group. The age- and smoking-status-adjusted relative risk ratio of having any macrovascular disease was 1.51 (95% CI 1.01-2.28, P = 0.048); coronary heart disease, 1.70 (95% CI 0.97-3.00, P = 0.063); albuminuria, 1.68 (95% CI 1.12-2.50, P = 0.01); and calcified aortic valve disease, 2.03 (95% CI 1.03-4.03; P = 0.042). Patients with good metabolic control, HbA1c <6.9% (<52 mmol/mol), had significantly lower Lp(a) levels than patients with poorer metabolic control, HbA1c >6.9% (>52 mmol/mol).
Conclusions: Lp(a) is a significant risk factor for macrovascular disease, albuminuria, and calcified aortic valve disease in patients with type 1 diabetes. Poor metabolic control in patients with type 1 diabetes is associated with increased Lp(a) levels.
© 2020 by the American Diabetes Association.