Adverse Outcomes in Relation to Polypharmacy in Robust and Frail Older Hospital Patients

Abstract

Objective: To explore the relationship between polypharmacy and adverse outcomes among older hospital inpatients stratified according to their frailty status.

Design and setting: A prospective study of 1418 patients, aged 70 and older, admitted to 11 hospitals across Australia.

Measurements: The interRAI Acute Care (AC) assessment tool was used for all data collection, including the derivation of a frailty index calculated using the deficit accumulation method. Polypharmacy was categorized into 3 groups based on the number of regular drugs prescribed. Recorded adverse health outcomes were falls, delirium, functional and cognitive decline, discharge to a higher level of care and in-hospital mortality.

Results: Patients had a mean (SD) age of 81 (6.8) years and 55% were women. Polypharmacy (5-9 drugs per day) was observed in 48.2% (n = 684) and hyper-polypharmacy (≥10 drugs) in 35.0% (n = 497). Severe cognitive impairment was significantly associated with nonpolypharmacy compared with polypharmacy and hyper-polypharmacy groups combined (P = .004). In total, 591 (42.5%) patients experienced at least 1 adverse outcome. The only adverse outcome associated with polypharmacy was delirium. Within each polypharmacy category, frailty was associated with adverse outcomes and the lowest overall incidence was among robust patients prescribed 10 or more drugs.

Conclusion: While polypharmacy may be a useful signal for medication review, in this study it was not an independent predictor of adverse outcomes for older inpatients. Assessing the frailty status of patients better appraised risk. Extensive de-prescribing in all older inpatients may not be an intervention that directly improves outcomes.

Keywords: Adverse outcomes; frailty; older inpatients; polypharmacy.