Relationship between polypharmacy and activities of daily living or in-hospital falls in elderly patients hospitalized for proximal femoral fracture: A retrospective cohort study

Polypharmacy is a risk factor for falls and decreased functional ability in older adults; however, its age-specific impact during rehabilitation remains unclear. This study was conducted at Tsurugi Hospital, located in Ishikawa, Japan. This study aimed to investigate the association between polypharmacy and outcomes such as in-hospital falls and activities of daily living at discharge in elderly patients hospitalized for proximal femoral fractures, focusing on age-group differences. This retrospective cohort study was conducted at a comprehensive rehabilitation ward. Patients aged ≥75 years admitted between April 2020 and March 2022 were included in the study. Participants were stratified into 2 age groups (75-89 and ≥90 years). Polypharmacy was assessed using 2 definitions: ≥5 medications (conventional) and age group-specific median cutoffs. The functional independence measure (FIM) scores and fall incidence were analyzed using appropriate statistical methods, including multiple regression and Bonferroni correction. Eighty-six patients (mean age 89.3 ± 5.2 years) were analyzed. In the 75-89 years age group, polypharmacy defined as taking ≥8 medications at discharge was significantly associated with lower cognitive FIM scores (median: 23 vs 32; r = -0.384, P = .016). Subscale analyses revealed significant negative associations in comprehension (r = -0.463, P = .004), problem-solving (r = -0.325, P = .047), and memory (r = -0.360, P = .026). In the same age group, multiple regression analysis further confirmed that taking ≥9 medications at discharge was an independent predictor of lower cognitive FIM scores (β = -0.466, P = .003). In contrast, in the ≥90 years group, cognitive FIM scores were significantly negatively predicted by the presence of dementia (β = -0.376, P = .005). In the overall sample, body mass index (β = 0.284, P = .007) and shorter postoperative hospitalization duration (β = -0.274, P = .010) were also associated with better cognitive FIM scores. The relationship between polypharmacy and functional outcomes varied by age group. These findings highlight the need for individualized discharge planning and medication management based on patient age and background.