Abstract
This study investigates the relationship between the composite dietary antioxidant index (CDAI) and the risk of all-cause and cardiovascular mortality in individuals with hypertension, aiming to provide dietary recommendations to reduce mortality. Data were sourced from the National Health and Nutrition Examination Survey (NHANES) database. The best cut-off for CDAI in relation to survival outcomes was determined using the maximally selected rank statistics method. Multivariate Cox regression analysis was used to examine the association between CDAI and mortality risks, and hazard ratios with 95% confidence intervals were calculated. Restricted cubic spline (RCS) curves were used to visualize the correlations. After analyzing data from 22,591 hypertensive adults, the optimal CDAI cut-off was found to be -1.23, categorizing participants into high and low CDAI groups. The results showed that the high CDAI group had a lower risk of cardiovascular and all-cause mortality (HR [95% CI]: 0.73 [0.61-0.87] and 0.79 [0.71-0.88], respectively). RCS analysis indicated a negative linear relationship with cardiovascular mortality and a nonlinear relationship with all-cause mortality. Subgroup and sensitivity analyses confirmed these findings. In conclusion, CDAI is a valuable predictor of long-term mortality risks in hypertensive individuals and can serve as a cost-effective tool for assessing their prognosis.