Adherence to antidepressants, rather than the adequacy of the prescribed antidepressant dosage, is predictive of treatment response in middle-aged and older patients who are being treated for depression in primary care, suggests a study in the American Journal of Geriatric Psychiatry.

A total of 187 older adults (mean age, 67.4 years) with depression were recruited from 2 primary care practices in New York (50.8%) and Michigan (49.2%) from January 2011 through December 2014. Patients in the study sample had received a newly prescribed antidepressant by their primary care provider for the treatment of depressive symptoms. Blinded investigators administered the 24-item Hamilton Rating Scale for Depression (HAM-D) to assess the severity of depression as well as depression response, the latter of which was defined as a 50% reduction on the HAM-D.

Additionally, the self-reported Brief Medication Questionnaire (BMQ) was administered to evaluate patient adherence to antidepressants. Adequate adherence was defined as ≥80% adherence, whereas full adherence was defined as patients who were adherent to prescribed antidepressant medications between 80 and 100% of the time at the 6- and 12-week follow-up assessments. All assessments were conducted at baseline, 6, 12, and 24 weeks. The study also examined adequacy of prescribed antidepressant dosage with the Composite Antidepressant (CAD) score.

The results revealed that at 12 and 24 weeks, 31.6% and 42.3% of patients had achieved depression response, respectively. Approximately 40.6% (n=76) of patients were receiving an adequate antidepressant dosage at the 6- and 12-week assessments. In addition, 62.6% (n=117) of patients reported they were fully adherent to their antidepressant regimen at 6 and 12 weeks. Greater adherence to the prescribed antidepressants was considered predictive of a higher likelihood of treatment response at 12 weeks (odds ratio [OR], 2.63; 95% CI, 1.19-5.84) and 24 weeks (OR, 3.09; 95% CI, 1.46-6.55). Receipt of an adequate dosage of antidepressant at 6 and 12 weeks was not associated with treatment response at 12 weeks (OR, 0.55; 95% CI, 0.27-1.11) or 24 weeks (OR, 1.26; 95% CI, 0.65-2.45).


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Limitations of this study included the lack of identification of specific antidepressant types as well as the lack of adjustment for side effect profiles in the examination of antidepressant adequacy.

Based on these findings, the study investigators recommended “targeting adherence improvement with personalized interventions such as Treatment Initiation Program, which can identify barriers early and build a personalized plan with effective strategies.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Sirey JA, Woods A, Solomonov N, et al. Treatment adequacy and adherence as predictors of depression response in primary care [published online April 23, 2020]. Am J Geriatr Psychiatry. doi: 10.1016/j.jagp.2020.04.014

This article originally appeared on Psychiatry Advisor