Clinical outcomes in older surgical patients with mild cognitive impairment.

INTRODUCTION: Older adults, including those with mild cognitive impairment (MCI), are increasingly undergoing surgery.

METHODS: Relative risks (RRs) of MCI alone or with delirium on adverse outcomes were estimated in an ongoing prospective, observational cohort study of 560 nondemented adults aged ≥70 years.

RESULTS: MCI (n = 61, 11%) was associated with increased RR of delirium (RR = 1.9, P < .001) and delirium severity (RR = 4.6, P < .001). Delirium alone (n = 107), but not MCI alone (n = 34), was associated with multiple adverse outcomes including more major postoperative complication(s) (RR = 2.5, P = .002) and longer length of stay (RR = 2.2, P < .001). Patients with concurrent MCI and delirium (n = 27) were more often discharged to a postacute facility (RR = 1.4, P < .001) and had synergistically increased risk for new impairments in cognitive functioning (RR = 3.6, P < .001).

DISCUSSION: MCI is associated with increased risk of delirium incidence and severity. Patients with delirium and MCI have synergistically elevated risk of developing new difficulties in cognitively demanding tasks.