Association between time-updated, cumulative exposure to frequent intradialytic hypotension and the 5-year risk of new-onset dementia. We used marginal structural Fine and Gray proportional subdistribution hazard models, treating death as a competing event, to estimate association between the time-updated, cumulative exposure to frequent intradialytic hypotension and the 5-year risk of new-onset dementia. Within a given 90-day exposure interval, we classified an individual as having frequent intradialytic hypotension if he or she experienced a nadir intradialytic systolic blood pressure <90 mm Hg in at least 30% of hemodialysis treatments. Supplementary Table S3 contains outcome and competing event definitions. We used inverse probability of exposure weighting to adjust for baseline and time-updated covariates listed in Supplementary Table S4. CI, confidence interval; HR, hazard ratio.