Osteoprotegerin is associated with silent coronary artery disease in high-risk but asymptomatic type 2 diabetic patients

OBJECTIVE- Osteoprotegerin (OPG) is an inhibitor of osteoclastogenesis, which has been recently involved in atherosclerosis. The relationship between coronary atherosclerosis and OPG has never been studied in asymptomatic type 2 diabetic patients. RESEARCH DESIGN AND METHODS- This is a nested case-control study; 162 asymptomatic type 2 diabetic patients were evaluated for silent myocardial ischemia using stress myocardial perfusion imaging; of 50 patients with positive results, 37 underwent coronary angiography, 20 of whom showed significant coronary artery disease (CAD group). Of 112 patients without silent myocardial ischemia, 20 subjects (NO-CAD group) were selected and matched by age and sex to patients with CAD. OPG, C-reactive protein, adiponectin, lipoprotein(a), albuminuria, and classical risk factors were measured. RESULTS- The percentages of subjects with OPG levels above median and with nephropathy were higher in the CAD group than in the NO-CAD group (70 vs. 25%, P = 0.004 and 50 vs. 5%, P = 0.001, respectively). LDL cholesterol levels were higher and HDL cholesterol levels lower in the CAD compared with the NO-CAD group (P = 0.033 and P = 0.005, respectively). No other variables were associated with CAD. Logistic regression analysis showed that OPG values above median (odds ratio 8.31 [95% Cl 1.18-58.68], P = 0.034) and nephropathy (21.98 [1.24-388.36], P = 0.035) were significant independent predictors of asymptomatic CAD in type 2 diabetic patients. CONCLUSIONS- Our investigation reports the first evidence of an independent association of OPG with asymptomatic CAD in type 2 diabetic patients. The results of this nested case-control study with 20 cases need to be confirmed in a larger population.