National Trends in Antidepressant Use in Australian Residential Aged Care Facilities (2006-2019).

Objectives: Antipsychotics have been the focus of reforms for improving the appropriateness of psychotropic medicine use in residential aged care facilities (RACFs). Comprehensive evaluation of antidepressant use in RACFs is required to inform policy and practice initiatives targeting psychotropic medicines. This study examined national trends in antidepressant use among older people living in RACFs from 2006 to 2019.

Design: National repeated cross-sectional study.

Setting And Participants: Individuals aged 65 to 105 years who were permanent, long-term (≥100 days) residents of Australian RACFs between January 2006 and December 2019 were included.

Methods: Annual age- and sex-adjusted antidepressant prevalence rates and defined daily doses (DDDs) supplied per 1000 resident-days from 2006 to 2019 were determined. Age- and sex-adjusted prevalence rate ratios (aRRs) and 95% confidence intervals (CIs) were estimated using Poisson and negative binomial regression models.

Results: A total of 779,659 residents of 3371 RACFs were included (786,227,380 resident-days). Overall, antidepressant use increased from 46.1% (95% CI, 45.9-46.4) in 2006 to 58.5% (95% CI, 58.3-58.8) of residents in 2019 (aRR, 1.02; 95% CI, 1.02-1.02). Mirtazapine use increased from 8.4% (95% CI, 8.2-8.5) to 20.9% (95% CI, 20.7-21.1) from 2006 to 2019 (aRR, 1.07; 95% CI, 1.07-1.07). Antidepressant use increased from 350.3 (95% CI, 347.6-353.1) to 506.0 (95% CI, 502.8-509.3) DDDs/1000 resident-days (aRR, 1.03; 95% CI, 1.03-1.03), with mirtazapine utilization increasing by 6% annually (aRR, 1.06; 95% CI, 1.06-1.06).

Conclusions And Implications: This nationwide study identified a substantial increase in antidepressant use among residents of Australian RACFs, largely driven by mirtazapine. With nearly 3 in every 5 residents treated with an antidepressant in 2019, findings highlight potential off-label use and suggest that interventions to optimize care are urgently needed.