Six-Month Outcomes of Co-Occurring Delirium, Depression, and Dementia in Long-Term Care

Objectives: To describe the 6-month outcomes of co-occurring delirium (full syndrome and subsyndromal symptoms), depression, and dementia in a long-term care (LTC) population. Design: Observational, prospective cohort study with 6-month follow-up conducted from 2005 to 2009. Setting: Seven LTC facilities in the province of Quebec, Canada. Participants: Newly admitted and long-term residents recruited consecutively from lists of residents aged 65 and older admitted for LTC, with stratification into groups with and without severe cognitive impairment. The study sample comprised 274 residents with complete data at baseline on delirium, dementia, and depression. Measurements: Outcomes were 6-month mortality, functional decline (10-point decline from baseline on 100-point Barthel scale), and cognitive decline (3-point decline on 30-point Mini-Mental State Examination). Predictors included delirium (full syndrome or subsyndromal symptoms, using the Confusion Assessment Method), depression (Cornell Scale for Depression in Dementia), and dementia (chart diagnosis). Results: The baseline prevalences of delirium, subsyndromal symptoms of delirium (SSD), depression, and dementia were 11%, 44%, 19%, and 66%, respectively. By 6 months, 10% of 274 had died, 19% of 233 had experienced functional decline, and 17% of 246 had experienced cognitive decline. An analysis using multivariable generalized linear models found the following significant interaction effects (P < .15): between depression and dementia for mortality, between delirium and depression for functional decline, and between SSD and dementia for cognitive decline. Conclusion: Co-occurrence of delirium, SSD, depression, and dementia in LTC residents appears to affect some 6-month outcomes. Because of limited statistical power, it was not possible to draw conclusions about the effects of the co-occurrence of some syndromes on poorer outcomes.