Potentially inappropriate medications with polypharmacy increase the risk of falls in older Japanese patients: 1-year prospective cohort study.

AIM: We aimed to evaluate whether potentially inappropriate medications (PIMs) increase the risk for adverse clinical outcomes including falls, emergency department (ED) visits and unplanned hospitalizations in older Japanese patients with chronic diseases, comparing the difference between patients with and without polypharmacy.

METHODS: A prospective observational cohort study was carried out in a Japanese outpatient primary care clinic. Baseline data was collected from January to March 2016. A total of 740 patients aged ≥65 years with chronic diseases were enrolled and were followed up at 1 year; falls, ED visits and unplanned hospitalizations were recorded. A questionnaire and review of the patients' medical records were used to collect information regarding sociodemographic status, comorbidities and medication prescriptions. PIMs were defined using the Screening Tool of Older Person's Prescriptions criteria version 2. Using logistic regression analysis, the incidence of falls, and ED visits and hospitalizations were compared between patients with and without PIMs, stratifying by number of prescriptions: those with five or more prescriptions and those with fewer than five prescriptions.

RESULTS: PIMs were identified in 32.3% of enrolled patients. After stratification by number of prescriptions, PIMs were significantly associated with falls in the group with polypharmacy (OR 2.03, 95% CI 1.11-3.69). This association was not seen in the group without polypharmacy. PIMs were not associated with ED visits or hospitalizations at the 1-year follow up upon multivariate analysis.

CONCLUSIONS: The combination of PIMs and polypharmacy might increase the risk of falls, therefore clinicians need to pay attention to both PIMs and polypharmacy. Geriatr Gerontol Int 2018; 18: 1064-1070.