Prognosis of delirium in hospitalized elderly: worse than we thought

BackgroundDespite 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. MethodsBetween October 2009 and July 2011, consecutively admitted older (70years 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 3months after discharge, elicited from the medical chart or post-discharge caregiver telephone interviews. ResultsOne thousand two hundred thirty-five in-patients (mean age 82.6years, 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 103days 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. InterpretationPoor 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. Copyright (c) 2013 John Wiley & Sons, Ltd.