Antidepressant medication to prevent depression relapse in primary care:the ANTLER RCT

BACKGROUND: There has been a steady increase in the number of primary care patients receiving long-term maintenance antidepressant treatment, despite limited evidence of a benefit of this treatment beyond 8 months. OBJECTIVE: The ANTidepressants to prevent reLapse in dEpRession (ANTLER) trial investigated the clinical effectiveness and cost-effectiveness of antidepressant medication in preventing relapse in UK primary care. DESIGN: This was a Phase IV, double-blind, pragmatic, multisite, individually randomised parallel-group controlled trial, with follow-up at 6, 12, 26, 39 and 52 weeks. Participants were randomised using minimisation on centre, type of antidepressant and baseline depressive symptom score above or below the median using Clinical Interview Schedule - Revised (two categories). Statisticians were blind to allocation for the outcome analyses. SETTING: General practices in London, Bristol, Southampton and York. PARTICIPANTS: Individuals aged 18-74 years who had experienced at least two episodes of depression and had been taking antidepressants for ≥ 9 months but felt well enough to consider stopping their medication. Those who met an International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, diagnosis of depression or with other psychiatric conditions were excluded. INTERVENTION: At baseline, participants were taking citalopram 20 mg, sertraline 100 mg, fluoxetine 20 mg or mirtazapine 30 mg. They were randomised to either remain on their current medication or discontinue medication after a tapering period. MAIN OUTCOME MEASURES: The primary outcome was the time, in weeks, to the beginning of the first depressive episode after randomisation. This was measured by a retrospective Clinical Interview Schedule - Revised that assessed the onset of a depressive episode in the previous 12 weeks, and was conducted at 12, 26, 39 and 52 weeks. The depression-related resource use was collected over 12 months from medical records and patient-completed questionnaires. Quality-adjusted life-years were calculated using the EuroQol-5 Dimensions, five-level version. RESULTS: Between 9 March 2017 and 1 March 2019, we randomised 238 participants to antidepressant continuation (the maintenance group) and 240 participants to antidepressant discontinuation (the discontinuation group). The time to relapse of depression was shorter in the discontinuation group, with a hazard ratio of 2.06 (95% confidence interval 1.56 to 2.70; p