The 6 and 12 month outcomes of older medical inpatients who recover from delirium

Abstract

To compare the 6 and 12 month outcomes of patients who recovered from delirium by 8 weeks with those who did not have an index episode. Older medical inpatients were assessed for delirium using the Confusion Assessment Method. All patients with delirium and a sample of patients without delirium were enrolled. Recovery from delirium at 8 weeks was determined using the Delirium Index and an algorithm based on DSM-III-R criteria. The primary composite outcome was cognitive or functional decline, institutional residence or death at 6 and 12 months. We fitted two logistic regression models to predict outcome odds ratio (OR) of delirium-recovered vs no delirium groups, adjusting for co-morbidity, severity of physical illness and demographic variables. In secondary analyses, we examined each component of the primary outcome separately. Of 361 patients enrolled, 59 died, 33 withdrew and one was lost to follow-up before 8 weeks. Of 268 patients assessed at 8 weeks, 115 and 95 were in delirium-recovered and no delirium groups, respectively. The 6 month OR for the primary composite outcome was 0.89 (95% CI 0.46, 1.70); the 12 month OR was 1.5 (95% CI 0.77, 2.90). Secondary analyses revealed a clinically important increase in mortality at 6 and 12 months. Among patients who survived, there were no significant differences in cognition, function or institutional status between delirium-recovered and no delirium groups at 6 and 12 months. If replicated, these findings have potentially important implications for clinical practice and research.