Inverse Association Between Persistence With Antidepressant Medication and Onset of Chronic Pain in Patients With Depression: A Retrospective Cohort Study.

Abstract

Despite the known involvement of depression in chronic pain, the association between persistence with and adherence to antidepressant medication and onset of chronic pain in patients with depression remains unclear. This retrospective cohort study used a Japanese claims database to extract data for adult patients with depression who were prescribed antidepressants between April 2014 and March 2020. Patients were divided into groups according to duration of continuous prescription of antidepressants (≥6 months [persistent group] and <6 months [nonpersistent group]) and medication possession ratio (≥80% [good adherence group] and <80% [poor adherence group]). The outcome was onset of chronic pain, which was defined as continuous prescription >3 months of analgesics and diagnosis of pain-related condition after discontinuation of the first continuous antidepressant prescription. The risk of onset of chronic pain was compared between the paired groups. A total of 1859 patients were selected as the study population and categorized as the persistent (n = 406) and nonpersistent (n = 1453) groups, and good adherence (n = 1551) and poor adherence (n = 308) groups. Risk of onset of chronic pain was significantly lower in the persistent group than in the nonpersistent group after controlling for confounding via standardized mortality ratio weighting (hazard ratio, 0.38; 95% confidence interval, 0.18-0.80; P = 0.011). There was no significant difference between the good and poor adherence groups. Antidepressant persistence for ≥6 months is recommended and may reduce the onset of chronic pain in patients with depression.