Association between polypharmacy and 2-year outcomes among Chinese older inpatients: a multi-center cohort study

The escalating global prevalence of polypharmacy presents a growing challenge to public health. In light of this issue, the primary objective of our study was to investigate the status of polypharmacy and its association with clinical outcomes in a large sample of hospitalized older patients aged 65 years and over. A two-year prospective cohort study was carried out at six tertiary-level hospitals in China. Polypharmacy was defined as the prescription of 5 or more different medications daily, including over-the-counter and non-prescription medications. Baseline polypharmacy, multimorbidity, and other variables were collected when at admission, and 2-year outcomes were recorded by telephone follow-up. We used multivariate logistic regression analysis to examine the associations between polypharmacy and 2-year outcomes. The overall response rate was 87.2% and 8713 participants were included in the final analysis. The mean age was 72.40 years (SD = 5.72), and women accounted for 42.2%. The prevalence of polypharmacy among older Chinese inpatients is 23.6%. After adjusting for age, sex, education, marriage status, body mass index, baseline frailty, handgrip strength, cognitive impairment, and the Charlson comorbidity index, polypharmacy is significantly associated with frailty aggravation (OR 1.432, 95% CI 1.258–1.631) and mortality (OR 1.365, 95% CI 1.174–1.592), while inversely associated with readmission (OR 0.870, 95% CI 0.764–0.989). Polypharmacy was associated with a 35.6% increase in the risk of falls (1.356, 95%CI 1.064–1.716). This association weakened after adjustment for multimorbidity to 27.3% (OR 1.273, 95%CI 0.992–1.622). Polypharmacy was prevalent among older inpatients and was a risk factor for 2-year frailty aggravation and mortality. These results highlight the importance of optimizing medication use in older adults to minimize the risks associated with polypharmacy. Further research and implementing strategies are warranted to enhance the quality of care and safety for older individuals exposed to polypharmacy. Chinese Clinical Trial Registry, ChiCTR1800017682, registered 09/08/2018.