Correlation between atherogenic index of plasma and coronary artery disease in males of different ages: a retrospective study

Background Atherogenic index of plasma (AIP) as a newly discovered blood lipid parameter was shown to be strongly correlated with coronary artery disease (CAD). However, the blood lipid levels changed with age, so we speculated that the correlation between AIP and CAD was also affected by age. Methods A retrospective study was performed on male patients with confirmed or suspected CAD who underwent coronary angiography (CAG) from July 2017 to March 2021. Patients were divided into younger, middle early, middle late, and elderly groups. Patients in each age group were further divided into the non-coronary artery disease (n-CAD) and CAD subgroups according to the CAG diagnostic results. The relationship between blood lipid parameters and CAD was assessed in each age group. Results Age-dependent changes of blood lipid levels were mainly found in CAD patients but not in n-CAD patients. With increased age, the levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol (LDL-C) and AIP were gradually decreased, whereas high-density lipoprotein cholesterol concentration was increased in CAD patients. Multivariate logistic regression analyses showed that AIP was an independent risk factor for CAD in middle early (OR 2.601; CI 1.160-5.832, P = 0.02) and middle late age group (OR 2.707, CI 1.201-6.100, P = 0.016), but not in the younger and elderly groups. LDL-C was an independent risk factor for CAD in all age groups. The areas under curve of AIP for detecting CAD in the middle early and middle late age groups were not higher than that of other blood lipid parameters. Conclusion Although this was a single-center study for males only, the correlation between AIP level and CAD risk was age-dependent. AIP was an independent risk factor for CAD in the middle-aged groups. However, the predictive value of AIP for detecting CAD was not better than that of the traditional blood lipid parameters such as LDL-C.