HIV-positive injecting drug users who are being treated with HAART are more likely to die than individuals from other HIV risk groups taking HIV therapy, according to data from the EuroSIDA study published in the November 19th edition of AIDS. However, the investigators found that non-HIV related causes accounted for the increased mortality amongst injecting drug users, and that injecting drug users were no more likely than other patients to experience a new AIDS-defining event or die of an HIV-related cause. The investigators believe that this implies that injecting drug users have a response to HAART comparable to other HIV risk groups.
Studies have provided conflicting data about the risk of HIV disease progression amongst injecting drug users taking HAART.
Therefore investigators from the EuroSIDA study set out to determine the differences in disease progression of different HIV risk groups after starting HAART. Investigators categorised illnesses and deaths as being HIV-related or non-HIV-related.
All the patients included in the study were taking HAART, had CD4 cell counts and viral load measurements available before the date they started anti-HIV treatment, and attended some follow-up appointments. Data were collected until the end of 2003.
A total of 3872 patients were included in the investigators' analysis. Sex between men accounted for most HIV infections (1797, 46%), injecting drug use for 819 infections (21%) and 991 cases of HIV were due to heterosexual sex.
Over a third (39%) of patients had never taken antiretroviral therapy before prior to starting HAART. Median CD4 cell count at the time of HAART initiation was 220 cells/mm3 and median viral load was 160,000 copies/ml. The median date for commencing HAART was June 1997, less than a year after HAART became widely available. This early start date is reflected in the type of antiretroviral regimen taken by patients: 71% of individuals in the investigators’ analysis took an anti-HIV combination based upon a single unboosted protease inhibitor, a regimen which would now be considered suboptimal for first-line therapy.
During almost 14,800 person-years of follow-up, a total of 499 new AIDS events occurred, and 296 patients died. However, two thirds of these deaths (194) were not related to HIV.
Compared to gay men, injecting drug users had a significantly increased incidence of new AIDS events/death (p = 0.03). However, this increased incidence was confined to non-HIV-related deaths (p
The investigators also found that a significantly higher proportion of injecting drug users (21% versus 4%, p
“The EuroSIDA study has demonstrated an increased clinical progression among [injecting drug users] after starting HAART”, write the investigators. However, they add, “the increased incidence was only found for non-HIV related deaths”. They conclude injecting drug users, "had no increased incidence of AIDS or HIV-related death. This suggests, on average, that [injecting drug users] who participated in EuroSIDA and started HAART had a comparable response to other exposure groups, were able to adhere to complex regimens, and benefited from a similar reduction in the risk of AIDS or HIV-related death.”
Reference
Mocroft A et al. Causes of death in HIV infection: the key determinant to define the clinical response to anti-HIV therapy. AIDS 18: 2333 – 2336, 2004.