Sex-specific association of weight-adjusted waist index with mortality in stroke survivors: A national longitudinal cohort study

Background and aims: The weight-adjusted waist index (WWI) is a novel indicator of obesity, and its association with mortality in stroke patients remains unknown. We aimed to explore these associations through a national longitudinal cohort study.

Methods and results: We included stroke survivors from the National Health and Nutrition Examination Survey (NHANES) 1999-2018 who were followed up until December 31, 2019. The study outcomes were all-cause and cardiovascular disease (CVD) mortality in stroke patients. A total of 1427 stroke patients were enrolled, and after a median follow-up duration of 83 months, 624 stroke patients died, including 251 from CVD. Kaplan‒Meier survival analyses indicated that WWI was significantly associated with the probability of survival over time in stroke patients (log-rank tests, both p < 0.0001). After adjusting for confounders, WWI was significantly and positively associated with all-cause and CVD mortality after stroke. Restricted cubic spline analysis revealed that WWI was linearly associated with all-cause mortality and nonlinearly associated with CVD mortality. Stratified analyses suggested that sex significantly influenced the effect of WWI on all-cause mortality in stroke patients. Additional body mass index (BMI) adjustments did not significantly change the results.

Conclusion: WWI was positively associated with all-cause and CVD mortality in stroke patients, independent of BMI. These effects were present only in men. These findings suggest that WWI is an independent prognostic factor in stroke patients and that maintaining appropriate WWI values can help improve the prognosis of stroke survivors.