Mortality falls in HIV/HCV coinfected Spaniards after the introduction of effective HIV treatment

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Mortality amongst Spanish injecting drug users coinfected with HIV and hepatitis C virus has fallen significantly since the introduction of effective HIV therapy in 1997, according to a study published in the January 2nd edition of AIDS.

“Since 1997, mortality rates have decreased in HIV/hepatitis C-positive subjects”, write the investigators who attribute this to the use of effective anti-HIV therapy and harm reduction programmes.

Between 1990 and 1996 a total of 3247 injecting drug users underwent voluntary testing for HIV, hepatitis C virus and hepatitis B virus. Investigators looked at mortality rates according to infection status until the end of 2002.

Glossary

statistical significance

Statistical tests are used to judge whether the results of a study could be due to chance and would not be confirmed if the study was repeated. If result is probably not due to chance, the results are ‘statistically significant’. 

person years

In a study “100 person years of follow-up” could mean that information was collected on 100 people for one year, or on 50 people for two years each, or on ten people over ten years. In practice, each person’s duration of follow-up is likely to be different.

hepatitis B virus (HBV)

The hepatitis B virus can be spread through sexual contact, sharing of contaminated needles and syringes, needlestick injuries and during childbirth. Hepatitis B infection may be either short-lived and rapidly cleared in less than six months by the immune system (acute infection) or lifelong (chronic). The infection can lead to serious illnesses such as cirrhosis and liver cancer. A vaccine is available to prevent the infection.

harm reduction

Harm reduction is a set of practical strategies and ideas aimed at reducing negative consequences associated with drug use (including safer use, managed use and abstinence). It is also a movement for social justice built on a belief in, and respect for, the rights of people who use drugs.

A total of 1381 (43%) of individuals were HIV-positive at baseline, 2759 (85%) were infected with hepatitis C virus, 1465 (45%) were infected with both HIV and hepatitis C and 149 (5%) were infected with hepatitis B. Individuals were followed-up for a median of 8.6 years.

Investigators had a total of over 26,000 person years of follow-up to analyse. In total 585 deaths were recorded, with 48% attributed to AIDS, 31% to violence and 21% to other causes. The overall mortality rate was a little over 2 per 100 person years.

Compared to injecting drug users who were negative for both HIV and hepatitis C, those who were infected with both viruses had a four-fold increased risk of death. Individuals who were only infected with hepatitis C had a 40% increase in the risk of death compared to HIV/hepatitis C – negative individuals, this was of borderline statistical significance.

The investigators noted that there was a 10% reduction in overall mortality amongst injecting drug users after 1997, the year when effective anti-HIV therapy became widely used. In further analysis they found that the introduction of potent HIV treatment had significantly altered mortality amongst individuals coinfected with HIV and hepatitis C. Before 1997, coinfected individuals had a five-fold increase in their risk of death compared to HIV/hepatitis C virus-negative drug users, but after 1997, coinfected individuals had a three-fold increased risk.

Mortality rates were further examined and the investigators found that after 1997 the risk of death fell by 20% for individuals coinfected with HIV and hepatitis C virus, but increased by 50% for injecting drug users who only had hepatitis C infection. These differences were statistically significant (p = 0.033).

“Mortality rates in HIV/hepatitis C-positive injecting drug users were extremely high, four times higher than mortality rates in HIV/hepatitis C-negative injecting drug users”, note the investigators. However, they observe “hepatitis C infection alone did not increase the risk of death after eight years of follow-up.” They add, “while mortality rates in HIV/hepatitis C-positive injecting drug users have decreased since 1997, statistically significant increases have been observed” in those who are uninfected with HIV but infected with hepatitis C.

References

Lumbreras B et al. Impact of hepatitis C infection on long-term mortality of injecting drug users from 1990 to 2002: differences before and after HAART. AIDS 20: 111 – 116, 2006.