HIV-infected injecting drug users (IDUs) now have equivalent survival rates to IDUs who are not infected with the virus, according to a large Spanish study.
Although over a decade’s use of antiretroviral therapy has seen dramatic survival gains in HIV-infected people generally, there have been doubts over whether this benefit has been seen in all groups of patients, specifically injecting drug users.
The Spanish researchers have compared survival rates between HIV-positive and HIV-negative IDUs from 1987 to 2004.
They split the period up into three time-frames: from 1987 to 1991 (the antiretroviral monotherapy era), 1992 to 1996 (the dual combination era during which methadone substitution treatment for heroin addiction was introduced into Spain) and 1997 to 2004 (the era of triple drug antiretroviral therapy, during which methadone programs became fully established in Spain).
A total of 1,206 IDUs were seen over that time at a drug treatment facility based at the University Hospital Germans Trias I Pujol, near Barcelona.
Most were men (81%), 59% were HIV-positive and 92% infected with hepatitis C virus (HCV). The researchers had an average of just over ten years of follow-up data.
The survival duration for HIV-negative IDUs remained constant throughout all three study periods.
As expected, mortality rates were substantially higher for HIV-positive IDUs in the first two study periods. At its peak, HIV-positive IDUs were over three times more likely to die than uninfected users.
But survival rates for this group improved significantly since 1997 and in the patients admitted from 1997 to 2004 the survival rates are virtually the same for both groups.
In fact the risk of dying was found to be actually slightly lower for those who are HIV-infected but this difference is not statistically significant.
The authors point out that only a third of the HIV-positive IDUs studied here were receiving antiretroviral therapy, and other factors are likely to have contributed to the improved survival among recently HIV-infected heroin users.
These include access to methadone programs, prophylaxis for opportunistic infections, harm reduction interventions as well as regular clinical care.
Most HIV-positive IDUs in this study did not have advanced immunosuppression and would not have been considered eligible for antiretroviral treatment.
This evidence of preserved immune function among HIV-positive IDUs has been seen in other studies and has been termed the “health drug user” effect and describes the ability of IDUs without debilitating HIV-related disease to maintain often heavy drug use.
No conclusions could be made about the impact of coinfection as practically all the HIV-infected users studied also had HCV infection, they add.
Muga R et al. Survival of HIV-infected injection drug users (IDUs) in the highly active antiretroviral therapy era, relative to sex- and age-specific survival of HIV-uninfected IDUs. Clinical Infectious Diseases 45 :370-376, 2007