Background Various overlapping risk factors lead to coronary artery disease (CAD). The atherogenic index of plasma (AIP) is a marker for CAD severity and progression. However, little is known about its contribution to the residual risk of CAD observed in the absence of all typical risk factors.Methods A prospective cohort study of 366 Indian patients undergoing coronary computed tomography (CT) angiography and diagnosed with stable CAD. Diabetes, hypertension, hypercholesterolemia, smoking, previous CAD, alcohol or lipid-lowering medication intake, renal, liver or thyroid dysfunction were exclusion criteria. Coronary stenosis was graded using the CAD-reporting and data system (CAD-RADS™) system. Lipid profile, HbA1c, uric acid, highly sensitive C-reactive protein (hsCRP) and anthropometric measurements were taken. AIP, triglyceride/high-density lipoprotein cholesterol (HDLc) and total cholesterol (Tc)/HDLc ratios were calculated. Independent predictors of CAD severity and the occurrence of major adverse cardiac events (MACE) during 2.57 (0.52) years of follow-up were identified using logistic regression and Cox proportional hazards regression.
ResultsSixty patients experienced a MACE during a cumulative 887.03 person-years. HbA1c, uric acid, hsCRP, Tc/HDLc and AIP were independent predictors of severe coronary lesions (CAD-RADS 4,5) on multivariate analysis with odds ratio 4.52 (2.37-8.61), 1.41 (1.08-1.84), 1.33 (1.09-1.62), 1.76 (1.27-2.44) and 1.29 (1.11-1.50), respectively. Only AIP and Tc/HDLc were independent predictors of MACE with hazard ratios of 1.41 (1.20-1.65) and 1.78 (1.33-2.39) besides patient age and CAD severity.Conclusion AIP is associated with both the severity of CAD and the occurrence of MACE within 3 years. It could serve as an effective marker of residual risk of CAD in patients devoid of traditional risk factors. Lipid-profile ratios, such as AIP are cost-effective and accessible parameters suitable for low and middle-income settings.