Predictors of Antidepressant Nonadherence Among Older Veterans With Depression

Most depression among older adults is treated in primary care, and many patients do not adhere to medication treatment. The U.S. Department of Veterans Affairs (VA) has recently introduced initiatives to address such treatment gaps. This study examined patient-reported antidepressant nonadherence during the acute treatment period (first four months after a prescription) and identified predictors of nonadherence in a sample of older veterans.

This was a prospective, observational study of 311 participants ages 60 and older who received care at three VA medical centers and who had a diagnosis of clinically significant depression and were given a new outpatient antidepressant prescription. Participants completed an initial interview and a follow-up interview at four months after treatment recommendation. Antidepressant adherence was measured with a well-validated self-report measure.

At four months, 29% of participants reported nonadherence to their antidepressant medication. In unadjusted analyses, nonadherence was significantly associated with being African American, having no spouse or significant other, having greater general medical comorbidity, and receiving the prescription in a primary care setting (versus a specialty mental health setting). In logistic regression models controlling for several variables (demographic, illness, and functional status variables; type of antidepressant; contact with a therapist; medical setting; and site of recruitment), two predictors remained significantly associated with nonadherence: African-American race (odds ratio [OR]=4.23, p<.001) and general medical comorbidity (OR=1.33, p=.002).

The two main predictors of nonadherence among older adults with depression were African-American race and general medical comorbidity. Results suggest that significant needs remain for important patient subgroups to improve antidepressant adherence.