Association of composite dietary antioxidant index and risk of death in patients with stroke

Abstract Background The Composite Dietary Antioxidant Index (CDAI) is a novel and comprehensive metric for evaluating overall antioxidant capacity. However, the association of the CDAI with all-cause and cardiovascular disease (CVD) mortality among stroke survivors remains undefined. Methods This study included 1,376 stroke survivors from the National Health and Nutrition Examination Survey (NHANES) spanning 1999 to 2018. Mortality outcomes were ascertained via the National Death Index. We utilized multivariate Cox regression models, incorporating restricted cubic spline plots, Kaplan-Meier survival analyses, and subgroup evaluations, to examine the link between CDAI and both all-cause and CVD mortality. Results During the mean follow-up period of 86.4 months, a total of 587 participants died. The weighted Cox regression indicated that, a one-unit rise in CDAI corresponded to a 6% decline in all-cause mortality (HR = 0.94, 95% CI = 0.91–0.98, p = 0.001) and a 9% decline in CVD mortality (HR = 0.91, 95% CI = 0.86–0.97, p = 0.002). When comparing individuals in the quartile 1 with those in quartile 4, it was found that the latter exhibited a 44% reduced risk of all-cause mortality (HR = 0.56, 95% CI = 0.41–0.76, p < 0.001) and a 62% decreased risk of mortality due to CVD (HR = 0.38, 95% CI = 0.21–0.70, p = 0.002). Conclusion The CDAI is inversely associated with all-cause and CVD mortality among stroke survivors. Specifically, higher CDAI levels are significantly linked to reduced risks of both all-cause and CVD mortality. Clinical trial number Not application.