Depression and alcohol consumption are two factors that can significantly impair people’s HIV medication adherence, according to a newly reported study in the journal Clinical Infectious Diseases.

In the study, Mariana Lazo, MD, of the Johns Hopkins Bloomberg School of Public Health in Baltimore, and her colleagues measured medication adherence in 1,944 men and women who were taking combination antiretroviral treatment. Adherence was measured at least twice over a five-year period, and participants’ adherence was categorized as either 100 percent or less than 100 percent. Researchers looked at whether a person’s adherence increased, failed to increase, or decreased.

Factors that were associated with increased adherence among men were older age and having a CD4 count between 350 and 500. For women, improved adherence was associated with having more (four or more) clinic visits during the study. One factor that predicted a failure to increase adherence, seen in both men and women, was the use of street drugs and alcohol.

The strongest association with decreased adherence in men was seen in those who were depressed, of a younger age, African American and in those with a yearly income of less than $20,000 or who were unemployed. In women, use of alcohol, drugs and tobacco was associated with decreased adherence. In both men and women, taking a treatment regimen that included a protease inhibitor was associated with decreased adherence compared with those taking a non-nucleoside reverse transcriptase inhibitor. Decreased adherence was also more common among those with a viral load of greater than 100,000 or a CD4 count below 200 cells.