['To investigate whether complications in postacute care (PAC) are associated with delirium persistence 30 days after PAC admission.', 'Observational cohort study.', 'Eight Boston-area PAC facilities.', 'Three hundred fifty individuals with delirium at PAC admission.', 'Participants were interviewed at PAC admission and 30 days later. Delirium presence was determined using the Confusion Assessment Method. Medical record reviews were performed to ascertain new cardiac, noncardiac, and geriatric syndrome complications in PAC. Complication status was also determined 30 days after admission or at PAC discharge, whichever came first.', 'Participants (mean age 83.6, 66% female) experienced the following incidence of PAC complications: cardiac complications (7%), noncardiac complications (21%), and geriatric syndrome complications (39%). Delirium persisted in 56% of participants 1 month after PAC admission. Neither cardiac nor noncardiac complications were associated with delirium persistence. Delirium persistence at 1 month was significantly greater in participants, with more geriatric syndrome complications (no complications, 51%; one complication 61%; ≥ 2 complications, 100%, adjusted P = .048). There was also a trend toward greater delirium persistence in participants with unresolved geriatric syndrome complications (no complications, 51%; resolved complication, 61%; unresolved complication, 68%; adjusted P = .10).'] Are complications in postacute care associated with persistent delirium?