Association between polypharmacy and the risk of requiring long-term care among community-dwelling older residents: A retrospective cohort study

Background

Polypharmacy has been increasing attention as it is associated with a number of health problems, especially adverse outcomes in older adults. However, there is insufficient evidence regarding the risk of polypharmacy and long-term care.

Methods

We analyzed a community-based retrospective cohort of residents of Goto City by combining data from health checkups, prescription information, and long-term care needs certification database. The study sample included residents aged 65–79 years in 2015 who were followed up for 4 years. The number of medications used was categorized as 0, 1–5, 6–9, and ≥10. The outcome was initiation of long-term care. Cox regression models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted for potential confounders.

Results

Among 1083 participants, 58 used long-term care for 4 years. Compared with participants taking no medication, the incidence of long-term care initiation was approximately double in those taking 1–5 medications, four times higher in people taking 6–9 medications, and 13 times higher in people taking ≥10 medications. After adjusting for potential baseline confounders, the number of medications was significantly associated with the initiation of long-term care services (1–5 drugs: adjusted HR 2.38, 95% CI 1.06–5.34; 6–9 drugs: adjusted HR 2.97, 95% CI 1.23–7.15; and ≥10 drugs: adjusted HR 5.54, 95% CI 1.89–16.23).

Conclusions

Among community-dwelling residents aged 65–79 years, the risk of requiring long-term care had a dose–response relationship with the number of prescribed medications.