Relationship of Pharmaceutical Promotion to Antidepressant Switching and Adherence: A Retrospective Cohort Study

Abstract

Patient nonadherence and early discontinuation of antidepressant treatment are common. Pharmaceutical promotion to consumers and physicians may influence this behavior. The objectives of this study were to explore whether promotional spending is related to early antidepressant switching, acute-phase adherence, and continuation-phase adherence. A retrospective cohort study was conducted with national promotional expenditure data merged with medical and prescription claims data from a large national health plan affiliated with i3 Innovus. Included were records for continuously insured adults with major depression who received a new prescription for an antidepressant: 5,010 were in the cohort assessed for switching, 4,457 were in the cohort assessed for acute-phase adherence, and 1,772 were in the cohort assessed for continuation-phase adherence. National promotional efforts were estimated by examining inflation-adjusted spending on direct-to-consumer advertising (DTCA) and physician detailing. Clinical guidelines were used to create proxies for aspects of treatment outcomes, including antidepressant switching and adherence in the acute phase and adherence in the continuation phase. Logistic regression models estimated the association between promotional variables and these outcomes. Patients taking medications that were more highly promoted to physicians were less likely to switch medications (odds ratio [OR]=.61) and were more likely to be adherent during the acute phase of treatment (OR=1.13). DTCA had little effect on switching or antidepressant adherence. Detailing to physicians was associated with lower rates of medication switching and had a positive relationship with patient adherence during early antidepressant treatment. This finding indicates that certain aspects of promotion may have beneficial effects on antidepressant use.