Trends, Patterns and Associated User Characteristics of Antidepressant Prescriptions in Older Adults: A Nationwide Descriptive Cohort Study in Denmark.

Background And Objective: Antidepressant use in older adults (≥ 65 years) is understudied in large population-based samples, particularly in recent years and regarding user characteristics. We aimed to describe the trends, patterns, and associated user characteristics of all antidepressant prescriptions redeemed by older adults at community pharmacies in Denmark during 2015-2019.

Methods: This register-based study used a cross-sectional design to characterize antidepressant prescription trends and patterns, and a cohort design to describe user characteristics associated with antidepressant prescription initiation. We used descriptive statistics to characterize trends and patterns, and Poisson regression for analyzing user characteristics.

Results: During the years 2015-2019, 17.9% of 1.2 million older adults redeemed 4.84 million antidepressant prescriptions, where 48.5% were selective serotonin reuptake inhibitors, followed by noradrenergic and specific serotonergic antidepressants (26.2%), serotonin-norepinephrine reuptake inhibitors (12.7%), tricyclic antidepressants (11.2%), and others (1.4%). Amitriptyline and nortriptyline, considered potentially inappropriate medications, were among the 10 most frequently redeemed antidepressants. Only 60.5% of prescriptions had a treatment indication of depression. Prescription-proportion trends by drug classes and individual antidepressants remained consistent. A higher incidence rate ratio (IRR) and 95% confidence interval (CI) of initiating antidepressants was associated with female sex (IRR 1.20, 95% CI 1.07-1.34), older age (e.g., 81-85 years vs. 65-70 years: IRR 1.74, 95% CI 1.44-2.11), living in rural areas (North Denmark vs. Capital Region: IRR 1.31, 95% CI 1.09-1.58), and having somatic and psychiatric diagnoses (e.g., per one psychiatric diagnosis: IRR 1.10, 95% CI 1.05-1.15), while a lower ratio was associated with being non-Western (vs. Danish: IRR 0.50, 95% CI 0.28-0.89) and having hospital contacts for psychiatric treatment (per each contact: IRR 0.96, 95% CI 0.93-1.00).

Conclusion: SSRIs were the most commonly redeemed antidepressants, with consistent trends in Danish older adults. Besides clinical conditions, sociodemographics, e.g., sex, age, ethnicity, and place of residence, may influence antidepressant use.