Lipoprotein (a) levels in diabetes mellitus: Relationship to metabolic control

Objective: To determine the influence of diabetes control on serum lipoprotein (a) concentrations. ■ Setting: Diabetes clinic of a large metropolitan public hospital, with primary- and secondary-care patients. Design: A cross-sectional study. Comparisons of lipoprotein (a) concentrations were made between a normal control group, a group of diabetic patients with glycated hemoglobin (HbA_1c) less than 8.0%, and a group of diabetic patients with HbA_1c of 8.0% or higher. Patients: Ninety-five normal controls and 93 diabetic subjects (49 with insulin-dependent diabetes mellitus and 44 with noninsulin-dependent diabetes mellitus). Results: Sixty diabetic subjects with HbA_1c levels of 8.0% or higher had higher (25 mg/dL) median levels of lipoprotein (a) when compared with either 93 normal controls (8.8 mg/dL) or 33 diabetic patients with HbA_1c less than 8.0% (7.5 mg/dL) (P = 0.008 and P = 0.012, respectively). A similar pattern of distribution of lipoprotein (a) levels according to degree of metabolic control was seen in patients with insulin-dependent diabetes mellitus and noninsulin-dependent diabetes mellitus. No difference in the lipoprotein (a) distribution was noted between diabetic men and women. No correlation was observed between lipoprotein (a) levels and total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels. Conclusion: Lipoprotein (a) levels are elevated in poorly controlled diabetic patients. Increased levels of lipoprotein (a) may be a contributing factor to the high risk for atherosclerosis observed in diabetic patients.