Subjects with more frequent episodes of intradialytic hypotension are more likely to experience vascular access thrombosis. Analyses adjusted for age, sex, black race, current smoking, diabetes mellitus, ischemic heart disease, congestive heart failure, peripheral vascular disease, hospitalization, serum albumin, hematocrit, mean predialysis SBP, intervention group, and clinical center. Error bars indicate 95% CIs. Ref, reference group. *P = 0.0063 versus quartile 1 (Q1).