Mannose-Binding Lectin Genotype and Phenotype in Patients With Type 2 Diabetes and Myocardial Infarction: A report from the DIGAMI 2 trial

OBJECTIVE: The present study characterizes mannose-binding lectin (MBL), an activator of the complement system and thereby important for inflammatory activation, in patients with diabetes and myocardial infarction. RESEARCH DESIGN AND METHODS: Serum (S)-MBL was determined at hospital admission in 387 patients with type 2 diabetes (median age 70 years; 68% male) with myocardial infarction, and genotyping was performed in 287 patients. Cardiovascular events (cardiovascular mortality and nonfatal myocardial infarction or stroke) were recorded during 2.5 years. RESULTS: Median S-MBL was 1,212 μg/l (interquartile range [IQR] 346–2,681 μg/l). Of the subjects, 54% in the geno- and phenotype subgroup had a high-coding MBL genotype (median S-MBL = 2,658 μg/l [IQR 1,715–3,829]) and 46% a low-coding MBL genotype (373 μg/l [100–765]). S-MBL did not correlate with age, BMI, creatinine clearance, glucose, or A1C. Cardiovascular events occurred in 136 (35%) patients. S-MBL did not predict events in univariable analyses (hazard ratio 0.93 [95% CI 0.85–1.01]; P = 0.09). In unadjusted analyses, the risk of events was lower in patients with a high genotype and S-MBL above the median for their genotype (0.49 [0.26–0.92]; P = 0.026) than for patients with a low genotype and S-MBL below the median for their genotype. The prediction capacity of the geno- and phenotype model was of borderline significance in adjusted Cox regression. CONCLUSIONS: Patients with type 2 diabetes and myocardial infarction have MBL genotypes that are similar to those known in the general population. The combination of a low-coding MBL genotype with a low S-MBL appears to be prognostically unfavorable, but the association is blunted by traditional risk markers.