Association between changes in potentially inappropriate medication use and adverse outcomes during hospitalization in older adults: A retrospective study

Purpose: To evaluate the association between the change in the number of PIMs in older adults during hospitalization and adverse outcomes. Methods: This retrospective cohort study was conducted in the internal medicine wards of a tertiary teaching hospital between May and December 2017. 3,460 patients (77.5 +/- 8.4 years, 60.4% male) were enrolled, and 206 patients died during hospitalization. PIMs were defined using the Beers Criteria as suggested by the American Geriatrics Society. Adverse outcomes studied were functional decline (a loss in 1 or more activities of daily living from admission to discharge), prolonged length of stay (LOS) (>14 days), and mortality. Results: 2258 patients (65.3%) had increasing PIMs during hospitalization. They tended to be younger (77.0 +/- 8.3 versus 78.5 +/- 8.5 years, p<0.001) and had lower numbers of PIMs at admission (0.4 +/- 0.8 versus 0.8 +/- 1.1, p<0.001). Increasing PIM use was strongly associated with greater functional decline (aOR 1.36, 95%CI 1.01-1.67, p=0.005), prolonged LOS (aOR 3.47, 95%CI 2.71-4.44, p<0.001) and higher mortality rate (aOR 2.68, 95%CI 1.75-4.12, p<0.001), even after adjusting for all covariates. We observed a strong association between adverse outcomes and increasing PIMs in older adults during hospitalization (p for trend <0.001). Conclusions: Older adults with increasing PIMs during hospitalization were at greater risk for functional decline, prolonged LOS, and mortality, especially in those with three or more PIMs. Further studies are needed to better understand the complex interactions and to evaluate the effectiveness of intervention programs to lower PIM number and improve discharge outcomes for patients who had increasing PIM use during hospitalization.