Is polypharmacy an independent risk factor for adverse outcomes after an emergency department visit?

This study aimed at verifying the role of polypharmacy as an independent risk factor for adverse health outcomes in older emergency department (ED) patients. This was a large (n = 2057) sample of older ED patients (≥65 years) participating in an observational cohort study. Polypharmacy and excessive polypharmacy were defined as having 6-9 drug prescriptions and 10 or more drug prescriptions in the last 3 months, respectively. The total number of medication prescriptions was also available. Outcome measures were in-hospital mortality; 30-day ED return; ED revisit, hospital admission, and mortality at 6 months. Logistic and Cox regression models as well as receiver operating characteristic curves using the Youden index and the area under the curve were calculated. Polypharmacy and excessive polypharmacy were present in 624 (30.3 %) and 367 (17.8 %) subjects, respectively. The mean number of prescriptions in the last 3 months was 5.7 (range 0-25) drugs. Polypharmacy and, particularly, excessive polypharmacy were constantly and independently associated with worse outcomes. A cut-off of 6 had the highest value of the Youden Index in predicting the majority of the adverse outcomes considered. Polypharmacy and excessive polypharmacy are independent risk factors for adverse health outcomes after an ED visit. Further studies are needed to clarify whether drug related issues (such as non-compliance, inappropriate or suboptimal prescribing, adverse drug reactions, and drug-drug or drug-disease interactions) or underlying multimorbidity and disease severity, as well as clinical complexity and frailty, are responsible for the negative outcomes associated with polypharmacy.