Polypharmacy as a risk factor for hospital admission among ambulance-transported old-old patients.

Aim: The aim of this study was to analyze the relationship between polypharmacy and hospital admission in ambulance-transported old-old patients.

Methods: A retrospective cohort study was conducted of consecutive old-old patients (aged ≥ 85 years) transported by ambulance to a community teaching hospital between April and December of 2013. Patients with out-of-hospital cardiopulmonary arrest were excluded. Data were collected from the computerized records on the demographics, chief complaints, vital signs, and level of consciousness at arrival, final diagnoses at discharge, and polypharmacy (≥5 medications). The primary outcome was requirement of hospital admission. We also analyzed symptomatic adverse drug events (ADEs).

Results: Of the 3,084 adults (aged ≥ 18 years) transported to the hospital during the study period, 381 (13%) were old-old patients. Of those, 233 (61%) were women, and 261 (69%) were admitted to the hospital. The mean number of their baseline medications was 6.8 ± 3.9, and 250/347 patients (72%) were suffering from polypharmacy. Twenty-seven of the patients (7%) had symptomatic ADEs. Although the ADEs were not related to polypharmacy ( = 0.437), logistic regression adjustments for age, sex, and vital signs at arrival showed that patients with polypharmacy were more likely to be admitted to the hospital than were patients without (odds ratio: 2.12 [95% CI, 1.03-4.43];  = 0.042).

Conclusions: Symptomatic ADEs due to polypharmacy were one of the most preventable causative factors leading to hospital admission of old-old patients. Polypharmacy could be a major risk for emergency admission to hospital.