The association between cognitive impairment and functional outcome in hospitalised older patients: a systematic review and meta-analysis.

BACKGROUND

in hospitalised older adults, cognitive impairments are common and may be associated with functional outcomes. Our aim was to systematically review this association.

METHOD

we systematically searched MEDLINE, CINAHL, AMED and PsycINFO from inception to April 2016. Non-English language studies were filtered out at search stage. All types of studies were considered for inclusion except reviews, conference abstracts, dissertations and case studies. Population: community-dwelling or institutionalised older adults aged 65 years or more, who are acutely hospitalised and have information on history of dementia and/or cognitive scores on admission. Setting: acute hospital (excluding critical care and subacute or intermediate care). Outcome of interest: change in a measure of physical function or disability between pre-admission or admission, and discharge or post-discharge. This review was registered on PROSPERO (CRD42016035978).

RESULTS

the search returned 5,988 unique articles, of which 34 met inclusion criteria. All studies were observational, with 30 prospective and 4 retrospective from 14 countries, recruiting from general medicine (n = 11), geriatric medicine (n = 11) and mixed (n = 12) wards. Twenty-six studies (54,637 participants) were suitable for the quantitative synthesis. The meta-analysis suggested that cognitive impairment was associated with functional decline in hospitalised older adults (risk ratio (RR): 1.64; 95% confidence interval (CI): 1.45-1.86; P < 0.01). Results were similar in subanalyses focusing on diagnosis of dementia (RR: 1.36; 95% CI: 1.05-1.76; P = 0.02; n= 2,248) or delirium (RR: 1.55; 95% CI: 1.31-1.83; P < 0.01; n= 1,677).

CONCLUSION

cognitive impairments seem associated with functional decline in hospitalised older people. Causality cannot be inferred, and limitations include low quality of studies and possible confounding.