Treatment interruptions explain higher HIV viral load in patients with depression and those who use stimulants

Inconsistent use of antiretroviral therapy is the main explanation for the higher viral loads observed in HIV-positive patients who are depressed or who use stimulant drugs, US investigators report in the February 1^st edition of the Journal of Acquired Immune Deficiency Syndromes.

“Inconsistent patterns of ART [antiretroviral therapy] utilization account for the effects of depression and stimulant use on higher HIV viral load,” comment the investigators.

The research team, lead by Dr Adam Carrico of the Center for AIDS Prevention Studies at the University of California, San Francisco, believe their findings have implications for the use of HIV therapy in prevention.

They write: “Adjuvant mental health and substance abuse treatment will be needed to promote sustained ART utilization, achieve viral suppression, and address HIV risk behavior among individuals with psychiatric comorbidities.”

Mental health screening and monitoring of drug use should therefore be incorporated into routine HIV care.

Faster HIV disease progression has been observed among patients taking antiretroviral therapy who are depressed or who use stimulant drugs such as cocaine, crack, or methamphetamine.

Researchers from Mental Health Healthy Living Project wished to see if this was because of inconsistent use of HIV therapy by patients who had symptoms of depression or who used stimulant drugs.

The investigators  therefore monitored the CD4 cell count and viral load of 603 patients over a 25-month period.

Information was gathered on the patients’ use of HIV treatment (continuous; intermittent; discontinued), and participants completed questionnaires to determine if they had depression and to assess their use of illicit drugs.

The patients’ mean age was 41 years, 80% were men, and 70% identified as gay or bisexual. The majority (54%) were African American.

On entry to the study, 94% of patients were taking antiretroviral therapy, but only 33% had an undetectable viral load. The average level of adherence reported over the 25 months of the study was 88%. A fifth of patients reported using stimulants on a weekly basis, 5% said that they used heroin, and 12% had a history of injecting drug use in the previous year.

Depression at baseline was associated with a 39% increase in the risk of interrupting HIV therapy, and weekly stimulant use increased the odds of treatment discontinuation 2.5 fold (51% vs. 25%).

The investigators’ first set of analysis showed that depression was associated with a 50% higher viral load during follow-up (p < 0.01). However, the association between depressive symptoms and viral load ceased to be significant when the investigators took into account the higher rates of treatment interruption or discontinuation among patients with mental health problems.

“Those with elevated depressive symptom severity may be more likely to discontinue ART regimens due to the pervasive sense of hopelessness and pessimism that are common features of depression,” comment the authors.

Weekly stimulant use predicted a 137% higher viral load (p < 0.05). However, after taking into account higher rates of discontinuation among individuals who regularly used this type of drug, the association between higher viral load and stimulant use ceased to be significant.

“Intermittent ART utilization may be more common among stimulant users because stochastic periods of binge are more common in this population,” suggest the investigators, “individuals may be more likely to stop taking ART regimens during periods of binge stimulant use but then re-initiate ART during periods of less frequent stimulant use or abstinence.”

The investigators therefore conclude that inconsistent use of HIV therapy is the main reason for the higher viral loads seen in patients with depression as well as for those who use stimulant drugs. However, they do not rule out possible biological factors, for example immune stimulation, or behavioural factors such as poor sleep and self-care.

Carrico AW et al. Psychiatric risk factors for HIV disease progression: the role of inconsistent patterns of antiretroviral therapy utilization. J Acquir Immune Defic Syndr 56: 146-50, 2011 (for the free abstract, click here).