Correlates of antiretroviral and antidepressant adherence among depressed HIV-infected patients.
Although crucial for efficacy of pharmacotherapy, adherence to prescribed medication regimens for both antiretrovirals and antidepressants is often suboptimal. As many depressed HIV-infected individuals are prescribed both antiretrovirals and antidepressants, it is important to know whether correlates of nonadherence are similar or different across type of regimen. The HIV Translating Initiatives for Depression into Effective Solutions (HI-TIDES) study was a single-blinded, longitudinal, randomized controlled effectiveness trial comparing collaborative care to usual depression care at three Veterans Affairs HIV clinics. The current investigation utilized self-report baseline interview and chart-abstracted data. Participants were 225 depressed HIV-infected patients who were prescribed an antidepressant (n=146), an antiretroviral (n=192), or both (n=113). Treatment adherence over the last 4 days was dichotomized as "less than 90% adherence" or "90% or greater adherence." After identifying potential correlates of nonadherence, we used a seemingly unrelated regression (SUR) bivariate probit model, in which the probability of adherence to HIV medications and the probability of adherence to antidepressant medications are modeled jointly. Results indicated that 75.5% (n=146) of those prescribed antiretrovirals reported 90%-plus adherence to their antiretroviral prescription and 76.7% (n=112) of those prescribed antidepressants reported 90%-plus adherence to their antidepressant prescription, while 67% of those prescribed both (n=113) reported more than 90% adherence to both regimens. SUR results indicated that education, age, and HIV symptom severity were significant correlates of antiretroviral medication adherence while gender and generalized anxiety disorder diagnosis were significant correlates of adherence to antidepressant medications. In addition, antiretroviral adherence did not predict antidepressant adherence (β=1.62, p=0.17), however, antidepressant adherence did predict antiretroviral adherence (β=2.30, p<0.05).