Contribution of classical and emerging risk factors to coronary artery disease in Asian Indians.

BACKGROUND: The merits and demerits of classical risk factors in coronary artery disease (CAD) are widely debated. We analyzed the role of conventional (age, gender, diabetes, hypertension, smoking) and non-conventional risk factors (anthropometrics, fasting blood sugar, atherogenic index of plasma - AIP, family history) in Asian Indians with CAD. METHODS: Out of 11,164 subjects (4855 affected, 6309 unaffected) enrolled in the Indian Atherosclerosis Research Study (IARS), 269 unaffected individuals with abnormal electrocardiogram and seven underage were excluded. Around 10,888 subjects along with two subsets, including 9888 individuals having family history information and 1616 individuals with intermediate Framingham risk score (FRS), were statistically analyzed using SPSS version 17.0 and R software. RESULTS: A combination of classical risk factors showed good discrimination between affected and unaffected individuals (C>0.85). Hypertension (OR 3.79) or male gender (OR 5.31) showed significant association with CAD when lipids were included or excluded from the predictive model, followed by age, diabetes and smoking. Hypertension and diabetes frequencies were higher in older patients (>55years) while smoking was more prevalent in younger patients (<55years). Family history and AIP provided a modest increase in C index over the classical factors (0.864 to 0.873), with 7.1% net reclassification in the intermediate FRS group. In CAD patients, 4% were classified as high risk by FRS, 52% were classified as having metabolic syndrome with revised criteria and over 90% had a high AIP score. CONCLUSION: Addition of AIP and family history to conventional risk factors improved risk discrimination in Asian Indians with CAD.