Association of potentially inappropriate medications and need for long-term care among older adults: a matched cohort study

BACKGROUND: With an increase in the aging population, the number of older adults who require long-term care (LTC) is growing, enhancing drug-related issues. The reduced capacity of LTC users to precisely utilize medical services poses additional challenges owing to restrictions in daily activities. We compared older adults who required LTC with those who did not require LTC to confirm differences in the use of potentially inappropriate medications (PIMs), frequently used PIMs, and associating factors in Korea. METHODS: Using the Korean National Health Insurance Service cohort data, adults aged ≥ 65 years as of 2017 who were LTC beneficiaries (at home and LTC facilities) were selected and matched 1:1 with a control group (LTC non-beneficiaries). PIM was defined based on the 2019 American Society of Geriatrics Beers criteria. PIM use and medical resource utilization according to LTC requirements were compared for one year after the index date. After correcting for other confounding variables, differences in the risk of PIM use on person-based according to LTC eligibility were assessed using multivariate logistic regression. RESULTS: Among the 13,251 older adults requiring LTC in 2017, 9682 were matched with counterparts and included. Among those who received an outpatient prescription including PIM at least once yearly, 83.6 and 87.6% were LTC beneficiaries and LTC non-beneficiaries, respectively (p < 0.001). Using the number of outpatient prescriptions as the baseline, 37.2 and 33.2% were LTC beneficiaries and LTC non-beneficiaries, respectively (p < 0.001). In both groups, elevated PIM use depended on increased medical resource utilization, as shown by increased outpatient visits and medical care institutions visited. Adjusting other influencing factors, the need for LTC did not significantly associated with PIM use (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.84–1.04); the number of drugs consumed (3–4: OR 1.42, 95% CI 1.25–1.61; 5–9: OR 2.24, 95% CI 1.98–2.53; 10 and more: OR 3.72, 95% CI 3.03–4.55; reference group: 2 and less), frequency of visits (7–15: OR 1.95, 95% CI 1.71–2.23; 16–26: OR 3.51, 95% CI 3.02–4.07; 27–42: OR 5.84, 95% CI 4.84–7.05; 43 and more: OR 10.30, 95% CI 8.15–13.01; reference group: 6 and less), and visits to multiple medical care institutions (3–4: OR 1.96, 95% CI 1.76–2.19; 5 and more: OR 3.21, 95% CI 2.76–3.73; reference group: 2 and less) emerged as primary influencing factors. PIMs mainly prescribed included first-generation antihistamines, benzodiazepines, and Z-drugs in both groups; quetiapine ranked second-highest among LTC beneficiaries. CONCLUSIONS: The LTC demand did not significantly associated with PIM utilization. However, the number of drugs consumed, and the pattern of medical resource use were important factors, regardless of LTC requirements. This highlights the need to implement comprehensive drug management focusing on patients receiving polypharmacy and visiting multiple care institutions, regardless of LTC needs.