Prognosis of delirium in hospitalized elderly: worse than we thought.

ABSTRACT

BACKGROUND: Despite treatment of the associated condition, delirious persons do not always recover for unknown reasons. We sought to determine early prognostic indicators of poor recovery following an episode of delirium in older medical in-patients. METHODS: Between October 2009 and July 2011, consecutively admitted older (≥70 years old) medical in-patients at the London Health Sciences Centre (Ontario) were screened for delirium. Delirious patients were followed. The primary outcome was poor recovery, in delirious patients, defined by death, long-term institutionalization, or functional decline (decreased activities of daily living), at discharge or 3 months after discharge, elicited from the medical chart or post-discharge caregiver telephone interviews. RESULTS: One thousand two hundred thirty-five in-patients (mean age 82.6 years, 42% men) were screened, delirium occurred in 355 (29%). Follow-up data was known on 342 (96%), and 237 (69%) had poor recovery 55 died (54 in hospital and one after discharge), 136 were permanently institutionalized (86 directly from hospital and 50 after discharge), and 46 had functional decline (at a median of 103 days after discharge). Poor recovery was associated in the derivation sample with advanced age, lower baseline function, hypoxia, higher delirium severity scores, and acute renal failure; this was predictive of poor recovery in the validation sample (receiver operating characteristic area 0.68, 95% confidence interval 0.57-0.79); however, even individuals with "low" risk had high (50%) poor recovery rates. INTERPRETATION: Poor recovery after delirium is common and associated with certain characteristics. However, even "lower risk" delirious individuals do poorly. More research is needed to understand prognostic factors in delirium.