HIV-positive patients with depression have poorer adherence to antiretroviral therapy than non-depressed individuals, according to a US study published in the March 1st edition of the Journal of Acquired Immune Deficiency Syndromes. The study also showed that depressed patients were less likely to achieve good suppression of HIV with anti-HIV treatment than non-depressed patients.
But the study also showed that treatment with SSRI (selective serotonin reuptake inhibitor) antidepressants was of value, with their use improving adherence to treatment. Furthermore, SSRI treatment boosted the chances of depressed patients achieving good viral suppression and increases in CD4 cell count.
SSRI treatment for depressed individuals has recently been the subject of controversy, with suggestions that the drugs are only of value for patients with severe depression. The results of this study suggest that therapy with SSRIs may also be of value to the estimated 30% of HIV-positive patients diagnosed with depression.
Adherence is the single most important factor under a patient's control influencing the success of their antiretroviral therapy. Mental health problems can have a negative impact on adherence, and depression is considered to be a risk factor for non-adherence to anti-HIV treatment.
Depression is widespread amongst patients with HIV and has also been shown to be associated with earlier death.
Investigators wanted to see if treatment with SSRI antidepressants improved adherence to antiretroviral therapy amongst depressed patients. They also wanted to see if such treatment for depression had an effect on viral load and CD4 cell counts.
They therefore performed a retrospective study involving patients who received their HIV care from Kaiser Permanente and Group Health Cooperative facilities between 2000 and 2003.
A total of 3359 patients were included in the investigators’ analysis. This included 1398 patients (42%) who had a diagnosis of depression in their medical records, and 508 of these patients had received treatment with an antidepressant from the SSRI class.
Over twelve months, mean adherence for all patients was 81%. For non-depressed patients mean adherence was 83%, compared to 79% for depressed patients who did not receive treatment with an SSRI, a significant difference (p = 0.01).
But mean adherence was 81% for patients treated with an SSRI (comparable to that seen in non-depressed individuals), and was 85% amongst those patients who were also adherent to their SSRI treatment – significantly better than the mean adherence seen amongst non-depressed patients (p = 0.01).
The investigators then looked at the impact of depression and SSRI treatment in viral load and CD4 cell count.
They found that depressed patients without SSRI treatment were significantly less likely to achieve an HIV viral load below 500 copies/ml after a year of anti-HIV treatment than non-depressed patients (p = 0.02). However, depressed patients who received SSRI therapy were just as likely to achieve this virological outcome as non-depressed patients.
Mean CD4 cell count increased by 152 cells/mm3 for the entire cohort. Overall there was no difference in CD4 cell increases between depressed and non-depressed patients. But the investigators found that depressed patients who had good adherence to SSRI therapy not only gained more cells than other depressed patients, but 19 cells/mm3 more than patients who were not depressed, a significant difference (p = 0.01).
Finally the investigators looked at the effect of SSRI therapy on patients who changed antiretroviral therapy. None of these patients had taken SSRI therapy before changing therapy. Taking SSRI treatment with a new antiretroviral regimen was not associated with better adherence, or in better virological control or improved CD4 cell gains.
“We demonstrate that a diagnosis of depression is associated with significantly reduced adherence to HAART regimens”, comment the investigators, adding that “depression was associated with significantly decreased odds of achieving HIV RNA levels below 500 copies/ml.”
The investigators believe that factors other than adherence may affect viral load in patients with depression and suggest “depression itself may affect viral control. Viral control was improved among patients prescribed SSRI medication, even more so if SSRI adherence is considered.”
They also draw attention to the superior gains in CD4 cell count seen in the patients with good adherence to SSRIs. They write, “these results are particularly important, because depression has been associated with earlier mortality in HIV-positive patients.”
“Our results have clinical implications”, add the investigators. They recommend that patients should be screened for depression, and that depressed patients should be offered SSRI treatment, “because compliant SSRI medication use was associated with improved HAART adherence and HIV laboratory parameters.”
Horberg MA et al. Effects of depression and selective serotonin reuptake inhibitor use on adherence to antiretroviral therapy and on clinical outcomes in HIV-infected patients. J Acquir Immune Defic Syndr 47: 384 – 390, 2008.