Inappropriate medication use in hospitalised oldest old patients across transitions of care

Background: Oldest old patients aged 85 years and over are at risk of experiencing potentially inappropriate medications (PIMs) and potential prescribing omissions (PPOs) across transitions of care. Geriatricians also face enormous challenges in prescribing medications for these patients. Methods: A mixed-methods, sequential explanatory design was undertaken of electronic medical records and semi-structured interviews with geriatricians at a public teaching hospital. Data were collected at four time points using the Screening Tool of Older Persons' potentially inappropriate Prescriptions (STOPP) and Screening Tool to Alert doctors to the Right Treatment (START). Results: Of 249 patients, the prevalence of at least 1 PIM varied between 36.9 and 51.0%, while the prevalence of at least 1 PPO varied between 36.9 and 44.6%. The most common PIM was use of proton pump inhibitors while the most common PPO was omission of vitamin D supplements in housebound patients or patients experiencing falls. Poisson regression analysis showed that PIMs were significantly associated with use of mobility aids, 1.430 (95% CI 1.109–1.843, p = 0.006), and number of medications prescribed at admission, 1.083 (95% CI 1.058–1.108, p < 0.001). PPOs were significantly associated with comorbidities, 1.172 (95% CI 1.073–1.280, p < 0.001), medications prescribed at admission, 0.989 (95% CI 0.978–0.999, p = 0.035), and length of stay, 1.004 (95% CI 1.002–1.006, p < 0.001). Geriatrician interviews (N = 9) revealed medication-related, health professional-related and patient-related challenges with managing medications. Conclusions: Inappropriate prescribing is common in oldest old patients. Greater attention is needed on actively de-prescribing medications that are not beneficial and commencing medications that would be advantageous. Tailored strategies for improving prescribing practices are needed.