Improvement in CD4 cell count with HAART associated with more unsafe sex, but not injecting in IDUs

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Injecting drug users who experienced an improvement in their CD4 cell count after starting HAART had an increased risk of engaging in more unprotected sex, according to a US study published in the April 15th edition of Clinical Infectious Diseases. However, the study found that improved immunological status was not related to more unsafe drug use, and the investigators emphasise that the overwhelming majority of individuals included in the study maintained both safer sexual and safer drug injecting behaviours after HAART initiation.

Although there has been considerable attention devoted by researchers into the sexual behaviours of gay men in the HAART era, little work has been undertaken on the sexual risk activities of drug users. Accordingly, investigators from the AIDS Link to Intravenous Experiences (ALIVE) study in Baltimore gathered data from 190 HIV-positive injecting drug users following the initiation of HAART between 1996 and 2000.

At twice-yearly visits, individuals were asked to complete a questionnaire enquiring about their sexual and drug use activities in the past six months. A blood sample was also obtained for CD4 cell testing. The investigators wished to establish if individuals were engaging in more sex since the initiation of HAART, and in particular more unprotected anal or vaginal sex, and/or more unsafe injecting.

Glossary

multivariate analysis

An extension of multivariable analysis that is used to model two or more outcomes at the same time.

hazard

Expresses the risk that, during one very short moment in time, a person will experience an event, given that they have not already done so.

sample

Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

intravenous

Injected into a vein.

At baseline the median age was 44 years and median CD4 cell count was 260 cells/mm3. A total of 20% of individuals had been diagnosed with AIDS prior to starting HAART and 71% were male.

The investigators found that after one year of follow-up, the median increase in CD4 cell count was 30 cells/mm3 on baseline and that 71.6% of individuals had been sexually active, 15% of whom had not been sexually active before starting HAART. In multivariate analysis, which controlled for a history of sexual behaviour, the investigators found that an increase in CD4 cell count was significantly and independently associated with increased sexual activity (adjusted relative hazard [ARH], 1.83; 95% CI, 1.22-2.73).

An association was also found between an improvement in CD4 cell count and an increase in the amount of unprotected sex. After two years of follow-up, the median CD4 cell count was 15 cells/mm3 higher than baseline, and 26.3% of individuals reported unprotected sex, 48% of whom had not engaged in unprotected sex in the year prior to starting HAART. In multivariate analysis which controlled for a history of unprotected sex before starting anti-HIV therapy, the investigators found that an increase in CD4 cell count from baseline was significantly and independently associated with unprotected sex (ARH, 3.29; 95% CI, 1.11-4.88). The investigators also found a significant and independent relationship between unprotected sex and starting HAART after 1997 (ARH, 1.94; 95% CI, 1.04-3.63).

When the investigators analysed the data for drug use behaviours after starting HAART, they found that, at the end of follow-up, 49% of individuals reported injecting drugs, 15% of whom had not injected drugs in the year before starting HAART. A total of 26.3% of individuals reported unsafe injecting practices during the follow-up period, and 52% of these individuals had not shared injecting equipment in the year before starting HIV therapy. However, in multivariate analysis neither drug use nor unsafe injecting practices were associated with an improvement in CD4 cell count after starting HAART.

The investigators stress that they found only a modest increase in the numbers of individuals reporting unsafe sex or drug use after starting HAART. However, “CD4 cell count increase after HAART initiation was found to be an important predictor of engaging in…unprotected sex after HAART initiation.” The investigators conclude that healthcare providers should counsel HIV-positive drug users taking HAART “about the continued importance of safe sexual and drug injection practices.”

Further information on this website

HAART optimism means HIV-positive IV drug users more likely to have unsafe sex and share needles - news story

References

Tun W et al. Increase in sexual risk behaviour associated with immunologic response to highly active antiretroviral therapy among HIV-infected injection drug users. Clinical Infectious Diseases 38: 1167-1174, 2004.