Association of the atherogenic index of plasma combined with obesity indices with cardiovascular disease and mortality

Both the atherogenic index of plasma (AIP) and obesity have been implicated in cardiovascular disease (CVD) risk. This study aimed to investigate the associations of AIP and AIP-obesity indices (AIP-WC, AIP-BMI, AIP-WHtR, AIP-WWI, and AIP-BRI) with CVD and mortality. This study enrolled 21,944 individuals from the National Health and Nutrition Examination Survey (NHANES) fielded during the years 1999–2018. Cox and logistic regression modeling, along with restricted cubic splines (RCS), served to assess the associations of AIP and AIP-obesity indices with all-cause mortality, CVD mortality, and CVD prevalence. The incremental predictive value of AIP and AIP-obesity indices was further assessed. Throughout an average follow-up period of 116 months, 3,326 all-cause deaths were documented, among which 1,042 were CVD deaths. AIP, AIP-WC, AIP-BMI, AIP-WHtR, AIP-WWI, and AIP-BRI were significantly associated with all-cause mortality, CVD mortality, and CVD prevalence. In the fully adjusted model, relative to the lowest-tertile participants, the highest-tertile participants of these indices had an elevated risk of 17.7–20.3% for all-cause mortality, an elevated risk of 30.3–33.8% for CVD mortality, and a 103.7–122.2% increase in the odds of CVD. RCS analyses indicated non-linear associations of AIP, AIP-WC, AIP-BMI, AIP-WHtR, AIP-WWI, and AIP-BRI with all-cause mortality and CVD prevalence, whereas linear associations were observed with CVD mortality. Incremental predictive value analyses showed that compared with AIP alone, AIP-WC, AIP-BMI, AIP-WHtR, AIP-WWI, and AIP-BRI provided superior risk reclassification and discrimination across all outcomes. AIP and AIP-obesity indices were significantly associated with CVD and mortality risk. AIP combined with obesity-related indices, particularly BRI, provides additional value for the stratification of CVD and mortality risk.