Determinants of Antidepressant Medication Prescribing in Elderly Residents of Aged Care Homes in Australia: a Retrospective Study

Background: Depression is underrecognized and poorly treated among older people living in aged care homes worldwide. Depression has been associated with higher rates of recurrence, disability, and death in older people.

Objectives: The primary objective of this study was to assess the determinants of antidepressant medication prescribing among older people living in aged care homes in Australia. A further objective was to investigate the anti-depressant medications in common use, doses of antidepressants, and concurrent pharmacotherapy among people receiving antidepressants.

Methods: A random sample of 500 deidentified medication review reports was extracted from a database containing >165,000 Residential Medication Management Review reports. Residents' demographic and clinical characteristics, medical diagnoses, and prescribed medications were systematically extracted from these reports. Logistic regression models were used to determine factors associated with the prescribing of any antidepressant, including tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and "other" antidepressants (eg, mianserin, mirtazapine, venlafaxine).

Results: The mean (SD) age of the residents was 84.0 (9.0) years. Seventy-five percent were female. The prevalence of antidepressant prescribing among these aged care home residents was 33.0%. SSRIs were more commonly prescribed than TCAs, monoamine oxidase inhibitors, and other antidepressants. Antidepressants were more likely to be prescribed in people treated for dementia with mood disorder (odds ratio [OR] = 9.70; 95% CI, 5.26-17.88), depression (OR = 13.28; 95% CI, 6.44-27.36), and Parkinson's disease (OR = 3.56; 95% CI, 1.37-9.23). SSRI prescribing was associated with dementia with mood disorder (OR = 5.85; 95% CI, 3.19-10.72) and depression (OR = 6.44; 95% CI, 3.38-12.26). TCA prescribing was associated with depression (OR = 2.95; 95% CI, 1.18-7.35) and concurrent benzodiazepine use (OR = 2.43; 95% CI, 1.03-5.72). Other antidepressant prescribing was associated with dementia with mood disorder (OR = 6.53; 95% CI, 3.15-13.50) and depression (OR = 5.00; 95% CI, 2.23-11.19).

Conclusions: There was preferential prescribing of SSRI antidepressants among these older aged care home residents with depression. Cognitive impairment alone was not significantly associated with antidepressant prescribing; however, these aged care home residents with dementia and mood disorders had an increased likelihood of being treated with antidepressants. The prescribing of TCAs was significantly associated with concurrent benzodiazepine use.