Lipoprotein(a) predicts progression of carotid artery intima-media thickening in patients with type 2 diabetes: A four-year follow-up.

backgroundThe aim of the study was to establish whether increased levels of serum lipoprotein(a) significantly contribute to an increase in intima-media thickness and the number of carotid artery plaques, and consequently to cardiovascular risk in patients with type 2 diabetes mellitus.

methodsLipoprotein(a) levels, intima-media thickness and the number of carotid artery plaques were determined at the beginning of the study in 146 patients with type 2 diabetes. Patients were divided into two groups according to serum lipoprotein(a) levels (> or <or=30 mg/dl). Intima-media thickness and the number of plaques were again determined after four years of follow-up. Intima-media thickness was assessed using high-resolution B-mode ultrasound.

resultsThe two groups of patients revealed no significant differences in baseline intima-media thickness (P = 0.112) in relation to lipoprotein(a) level. After follow-up, intima-media thickness was significantly greater in patients with higher lipoprotein(a) levels (1.24 + 0.22 vs. 1.15 + 0.17 mm, respectively; P = 0.005). The mean increase in thickness over four years was 0.12 mm (0.030 mm/year) in the group with low lipoprotein(a) levels and 0.17 mm (0.043 mm/year) in the group with high lipoprotein(a). Multivariate analysis indicated that intima-media thickness depended on lipoprotein(a), and not on triglyceride, HDL-cholesterol levels or waist-to-hip ratio. No significant difference in baseline and follow-up number of plaques was observed between the study groups (P = 0.276 vs. P = 0.355, respectively). Although the group with lipoprotein(a) >30 mg/dl had more cardiovascular events, the difference was not statistically significant.

conclusionsThese results indicate that lipoprotein(a) is an independent, genetically determined risk factor closely associated with progression of intima-media thickness in type 2 diabetes.