Self-efficacy and depression as mediators of the relationship between pain and antiretroviral adherence

The goals of this study were to examine the association between pain and antiretroviral adherence and to estimate the mediating effect of adherence self-efficacy and depression symptom severity. Surveys using audio computer-assisted self-interview were conducted among 70 HIV-infected current and former drug users enrolled in a methadone program. We assessed antiretroviral adherence and adherence self-efficacy using questions from the Adult Clinical Trials Group survey. We considered participants adherent if they reported taking at least 95% of prescribed antiretrovirals over the past seven days. We assessed depression symptom severity using the depression subscale of the Brief Symptom Inventory. Participants reported pain of any duration in response to a question from the Brief Pain Inventory. Participants reporting pain were 87% less likely to be classified as adherent compared to those without pain (Unadjusted OR = 0.13, 95%CI: 0.03-0.52). When we examined adherence self-efficacy as a mediator of the relationship between pain and adherence, criteria for partial mediation were met. Adjusting for self-efficacy, the beta coefficient for pain decreased by 23% but the independent relationship between pain and antiretroviral adherence was maintained. Mediation criteria were not met when we examined the mediating effect of depression symptom severity on the relationship between pain and adherence. Adjusting for depression symptom severity, the beta coefficient for pain decreased by 9% and the relationship between pain and antiretroviral adherence remained significant. Our results indicate that neither adherence self-efficacy nor depression symptom severity fully mediated the relationship between pain and adherence. HIV providers should recognize the potential impact of pain on antiretroviral adherence among current and former drug users.