Evaluation of the use and impact of potentially inappropriate medicines in Australian residential aged care

<p dir="ltr">Potentially inappropriate medicines (PIMs) are drugs that can cause more harm than benefit, especially when misused or prescribed without considering individual factors such as age, comorbidities, and drug interactions. The use of PIMs in residential aged care facilities (RACFs; also known as nursing homes, care homes or long-term care facilities) is a growing concern, yet limited research has focused on its prevalence, risks, or prescribing trends, particularly during disruptions like the COVID-19 pandemic. Complementary medicines (CMs) include diverse medical and health care practices and medicinal products that, without proper clinical oversight, may contribute to PIMs use when combined with prescribed medicines. This research addresses a significant gap by analysing the patterns and impact of PIMs use among older adults in Australian RACFs. The new knowledge generated will enhance awareness of the extent of PIMs use in Australian RACFs and its impact on resident outcomes, guiding medicines policies to prioritise and reduce PIMs. This thesis involved the conduct of retrospective cohort studies using routinely collected electronic data which included the details of medication use by all permanent residents aged ≥65 in 23 RACFs in Sydney, Australia. The updated 2023 Beers Criteria were applied to assess PIMs use and CMs use. Chapter 2 assessed the prevalence, types, and factors associated with potentially inappropriate psychotropic medicines (PIPMs) use as well as facility variation in PIPMs use. The findings revealed a high rate of PIPMs use (40% of the residents), with considerable variation across facilities (23.3% to 57.0%). Dementia, pain, depression, and anxiety disorders were identified as risk factors for increased PIPMs use. The overall median number of days residents were exposed to PIPMs was 91 days (IQR 6-320), while the median proportion of days covered by at least one PIPMs was 39.3% (IQR 2.6-86.6%). Chapter 3 assessed the impact of PIPMs on falls, one of the most prevalent and pressing health issues in RACFs. Three outcome groups were considered: all falls, injurious falls, and falls requiring hospitalisation. The results revealed that falls were common among PIPMs users, leading to injury and hospitalisation. PIPMs users had a significantly greater rate of falls overall compared to non-users (IRR 1.29; 95% CI 1.16-1.44) for all outcomes after adjusting for other factors such as age, sex, and health status (i.e., arthritis, fracture, dementia cognitive impairment, anxiety, diabetes mellitus, visual impairment, delirium, Parkinson’s disease and ATC (Anatomical Therapeutic Chemical Classification) level 1 medicines). Specifically, 70% of PIPMs users experienced at least one fall, with one in three requiring hospital admission, compared to 60% of non-PIPMs users experiencing a fall. Chapter 4 explored the changes in psychotropic and PIPMs use before and during the first COVID-19 lockdown among existing and new residents. No statistically significant difference was found in the use of any psychotropic medicine for existing (OR 0.98; 95% CI 0.85-1.14) and new residents (OR 0.87 95% CI 0.53-1.45), nor for the use of PIPMs among existing residents (OR 0.95; 95% CI 0.82-1.10) and new residents (OR 0.77; 95% CI 0.46-1.30) before and during the first Sydney COVID-19 lockdown. In Australian RACFs, CMs are documented in electronic medicines record systems alongside prescription medicines, with daily usage monitored. CMs use may contribute to PIMs use, particularly when taken alongside prescribed medicines without appropriate clinical management. Chapter 5 showed the prevalence and predictors of CMs use and examined differences in CMs use by facility for residents of RACFs. The study results revealed that nearly four in five residents (78.4%) took at least one CMs product. The prevalence of residents using at least one CMs ranged from 54% to 88% between facilities. Vitamin D emerged as the most used CMs (61.4% of residents) and 41.2% of residents used 2 or more CMs. This thesis highlights the need for quality improvement initiatives which target PIMs use including, regular medicine reviews, and fall prevention strategies. Additionally, the results demonstrate the need to examine CMs use as part of comprehensive medicine reviews given their high rates of use. These findings provide new evidence to inform medicine policies, prioritize PIMs reduction, and develop evidence-based strategies to enhance medicine safety in aged care.</p><p><br></p>