(ASPOT18) Antidepressant long-term and potential high-risk prescribing in two Scottish health boards: a cross-sectional analysis

Background: The use of antidepressants (ADs) has increased substantially over recent decades. Their widespread long-term use in milder forms of depression and insomnia is concerning, particularly in older adults with comorbidities and polypharmacy. In 2012, 2015 and 2018, NHS Scotland polypharmacy guidelines were published to reduce the burden of inappropriate polypharmacy.

Objectives: The aim of this study is to examine and compare the prevalence of AD use and the proportion of AD use with potential deprescribing indications (PDI) in two Scottish health boards in 2012 and 2019.

Methods: This is a repeated population-based cross-sectional study of community-dispensed prescribing for all 609,299 people aged 18 years or older resident in the Tayside and Fife regions of Scotland. AD users were those with one or more AD prescription in 2nd quarters of 2012 and 2019. PDIs (i.e., long-term use and high-risk use) were defined by a previously expert consented indicator list. The rates of (1) AD use and (2) AD use with PDIs were calculated for the respective second quarter of 2012 and 2019. A binary logistic regression model was used to examine patient and treatment characteristics associated with the presence of PDI due to long-term use among AD users.

Results: Between 2012 and 2019, the proportion of people aged 18 years or older who were dispensed one or more AD increased from 12.0% to 15.3%. In the 2nd quarter of 2019, the average age of AD users was 54.3 years (SD = 17.7) and 67.6% were female. The most commonly dispensed ADs were selective serotonin reuptake inhibitors (55.3%) followed by tricyclic antidepressants (27.9%) and mirtazapine (14.3%). Antidepressant PDIs due to long term use increased from 54.3% to 62.0%, while PDIs due to high-risk use decreased from 44.2% to 40.4%. High-risk use most commonly related to risk of falls (24.9% of all AD users) and risk of QTc prolongation (10.8%). Almost a third (29.0%) of AD users had PDIs with respect to both long term and high-risk use. Having AD deprescribing opportunities due to long-term use was most strongly associated with female gender (adjusted OR 1.3; 95% CI 1.3-1.4), number of drugs dispensed (≥ 15 drugs; adjusted OR 3.2; 95% CI 2.9-3.5) and high age (60 - 69; adjusted OR 5.7; 95% CI 5.3-6.1).

Conclusions: While antidepressants have an irreplaceable role in the treatment of severe forms of depression and anxiety, their widespread long-term and high-risk use (despite ongoing efforts to reduce inappropriate polypharmacy) is concerning. This study identified patients with potential deprescribing indications (PDIs), who might benefit from a critical review of antidepressant continuation. Further research is necessary to assess the performance (sensitivity and specificity) of the indicator set in identifying actual deprescribing opportunities.