The Start Predicts the Finish: Factors Associated With Antidepressant Nonadherence Among Older Veterans During the Acute and Maintenance Treatment Phases

Objective: To best prevent depression relapse and reduce recurrence, an understanding of the factors associated with continued maintenance treatment is needed. This study compared factors associated with antidepressant nonadherence during the acute (ie, during the first 4 months) and maintenance (ie, during 12 months) treatment phase among older veterans with depression.

Methods: In this prospective, observational study of 278 older veterans with depression (Patient Health Questionnaire-9 score ≥ 5), patients had been given a new antidepressant prescription between 2008 and 2011. Participants completed initial and follow-up interviews at 4 and 12 months. Medication adherence was assessed by the Brief Medication Questionnaire. A generalized estimating equation was used to determine patient factors associated with nonadherence at each time point.

Results: Nearly a third of veterans were nonadherent at 4- and 12-month follow-up. In adjusted analyses, nonadherence was significantly associated with African American race (adjusted odds ratio [AOR] = 2.69, 95% CI, 1.30-5.57; P = .01), being unmarried (AOR = 1.84; 95% CI, 1.16-2.92; P = .049), greater medical comorbidity (AOR = 1.30; 95% CI, 1.13-1.49; P < .001), functional impairment (AOR = 1.34; 95% CI, 1.10-1.63; P = .01), and self-reported side effects (AOR = 2.48; 95% CI, 1.57-3.94; P < .001) at both 4 and 12 months. Depression or anxiety severity did not predict antidepressant adherence at either time point.

Conclusions: Rates of and factors associated with antidepressant nonadherence were similar at 4 and 12 months. Further work is needed to develop tailored treatment programs to engage older veterans at higher risk of nonadherence in the early treatment period, which may ultimately help to both achieve remission and reduce relapse and recurrence.