Cognitive and functional change in skilled nursing facilities: Differences by delirium and Alzheimer's disease and related dementias.

Background: Whether cognitive and functional recovery in skilled nursing facilities (SNF) following hospitalization differs by delirium and Alzheimer's disease related dementias (ADRD) has not been examined.

Objective: To compare change in cognition and function among short-stay SNF patients with delirium, ADRD, or both.

Design: Retrospective cohort study using claims data from 2011 to 2013.

Setting: Centers for Medicare and Medicaid certified SNFs.

Participants: A total of 740,838 older adults newly admitted to a short-stay SNF without prevalent ADRD who had at least two assessments of cognition and function.

Measurements: Incident delirium was measured by the Minimum Data Set (MDS) Confusion Assessment Method and ICD-9 codes, and incident ADRD by ICD-9 codes and MDS diagnoses. Cognitive improvement was a better or maximum score on the MDS Brief Interview for Mental Status, and functional recovery was a better or maximum score on the MDS Activities of Daily Living Scale.

Results: Within 30 days of SNF admission, the rate of cognitive improvement in patients with both delirium/ADRD was half that of patients with neither delirium/ADRD (HR = 0.45, 95% CI:0.43, 0.46). The ADRD-only and delirium-only groups also were 43% less likely to have improved cognition or function compared to those with neither delirium/ADRD (HR = 0.57, 95% CI:0.56, 0.58 and HR = 0.57, 95% CI:0.55, 0.60, respectively). Functional improvement was less likely in patients with both delirium/ADRD, as well (HR = 0.85, 95% CI:0.83, 0.87). The ADRD only and delirium only groups were also less likely to improve in function (HR = 0.93, 95% CI:0.92, 0.94 and HR = 0.92, 95% CI:0.90, 0.93, respectively) compared to those with neither delirium/ADRD.

Conclusions: Among older adults without dementia admitted to SNF for post-acute care following hospitalization, a positive screen for delirium and a new diagnosis of ADRD, within 7 days of SNF admission, were both significantly associated with worse cognitive and functional recovery. Patients with both delirium and new ADRD had the worst cognitive and functional recovery.