Impact of inappropriate drug use on physical performance among a frail elderly population living in the community

Objective The criteria for inappropriate drug use developed by Beers have been widely used in drug utilization reviews to assess the quality of prescribing, but there is still inconclusive evidence that these criteria can impact on patient outcomes. The aim of the present study was to evaluate the relationship between the use of inappropriate drugs and measures of physical performance, muscle strength and functional status in an elderly population (80+ years). Methods Data are from the baseline evaluation of 364 subjects enrolled in the ilSIRENTE study, a prospective cohort study performed in a mountain community living in the Sirente geographic area (L'Aquila, Abruzzo) in Central Italy. Physical performance was assessed using the physical performance battery score (SPPB), which is based on three timed tests: 4-m walking speed, balance and chair stand tests. Muscle strength was measured by hand grip strength. Inappropriate drug use was defined by the 2003 Beers criteria. Analyses of covariance were performed to evaluate the relationship of inappropriate drugs with physical function. Results In the unadjusted model, all of the physical performance, muscle strength and functional measures showed significant associations with inappropriate drug use. Following adjustment for potential confounders, which included age, gender, physical activity level, cognitive performance scale, comorbidity, lung diseases and diabetes, these associations were still statistically significant for the physical performance battery score [non-users inappropriate drugs: 7.0; standard error (SE): 0.1; users inappropriate drugs: 6.1; SE: 0.2; p=0.007] The 4-m walking speed, physical performance battery score and Total Activities of Daily Living (ADL) scale score showed worsening results among subjects using two inappropriate medications compared with subjects using one inappropriate drug or none at all. Conclusions The use of inappropriate medication (as defined by Beers 2003 criteria) was found to be common among the elderly Italian study cohort living in the community. Our results suggest that among old-old subjects the use of inappropriate drugs is associated with impaired physical performance.