Effects of HIV Medication Complexity and Depression on Adherence to HIV Medication

Background: While much is known about the association between drug regimen complexity and drug adherence, little is known about how this association is affected by patient depression. Objective: To examine whether the relationship between medication adherence and highly active antiretroviral therapy (HAART) regimen complexity varied with mental health status. Methods: The analysis included 1192 respondents to HCSUS who were receiving HAART at the second HCSUS follow-up interview (1997-8). Self-reported past-week HAART adherence, current mental health status, and an aggregate measure of regimen complexity were used in the analysis. Regression models with interactions between mental health status and medication complexity were estimated to assess differential associations with adherence. Results: Patients with high depressive/anxiety symptoms had lower odds of adherence to HAART medication (odds ratio &lsqb;OR&rsqb; - 0.78; p < 0.05) than those with low depressive symptoms at mean medication complexity. However, this association was found to vary by HAART medication complexity. Under high depressive symptoms, odds of adhering to a low-complexity regimen were 9% lower than odds of adhering to a regimen of mean complexity (OR - 0.91). Under low depressive symptoms, odds of adhering to a low-complexity regimen were 44% higher than for a regimen of mean complexity (OR - 1.44). In contrast, odds of adhering to a highly complex regimen compared with a regimen of mean complexity were 10% higher under high depressive symptoms (OR - 1.10) and 30% lower for low depressive symptoms (OR - 0.70). Thus, high levels of depression have ORs for adherence that increase with HIV drug complexity, while low levels of depression have ORs for adherence that decline with HIV drug complexity (the two trends differ by p - 0.10). In a second measure of mental health, similar results were found between low and high emotional well-being (the two trends differ by p < 0.05). Conclusion: While individuals with poorer mental health generally have poor adherence, these individuals may have been preferentially targeted with adherence support interventions as the medication regimen complexity increased. Physicians should now begin to target adherence interventions to patients with less complex HIV regimens.