Starting antiretroviral therapy is
associated with reductions in sexual risk-taking and injecting among
HIV-positive drug users, according to US research published in the online
edition of AIDS. There was a 75% reduction in the risk of
unprotected sex, whereas the risk of injecting drugs fell by over a third.
However, among the small sub-set of patients who continued to inject, the risk of
sharing injecting equipment almost doubled.
Overall, the investigators were encouraged by
their findings, writing: “Our data do not support the premise that HAART
[highly active antiretroviral therapy] is associated with generally increased
risky behavior among IDUs [injecting drug users].”
Thanks to antiretroviral therapy, many
HIV-positive people now have an excellent prognosis. There is also compelling
evidence that virologically effective antiretroviral treatment significantly
reduces the risk of HIV transmission.
However, there is some concern that the
prevention benefits of treatment could be offset by increases in levels of
risky sex or injecting practices. Studies looking at this issue have yielded
Investigators from the AIDS Linked to the
IntraVenous Experience (ALIVE) cohort therefore designed a study involving 362
HIV-positive people with a history of injecting drug use in Baltimore.
Researchers monitored sexual activity and injecting
behaviour in the year before initiation of HIV therapy and for up to five years
Most of the participants (71%) were male and
African American (95%).
In the year before starting HIV therapy,
67% of participants reported any sexual activity, almost half (48%) engaged in
unprotected sex, a majority (61%) injected drugs and approximately a quarter (27%)
reported sharing injecting equipment.
Overall, starting antiretroviral therapy
was accompanied by a decline in risky behaviour. The proportion of participants
reporting any sex fell to 48%, unprotected sex to 17%, injecting drug use to
34% and sharing injecting equipment fell to 16%.
After taking into account confounding
factors, the investigators calculated that starting antiretroviral therapy
reduced the risk of unprotected sex by 75% (aOR = 0.25; 95% CI, 0.19-0.32).
“We found no evidence of sexual behavioral
risk compensation following initiation of HAART,” comment the investigators.
“Among IDUs who remained sexually active, we observed a significant decline in
unprotected sex after HAART initiation.”
The risk of injecting drug use fell by 38% (aOR
= 0.62; 95% CI, 0.51-0.75).
These reductions in risk behaviour were
sustained for up to five years after HIV treatment was started.
However, for the 16% of participants who
continued to share needles after initiating therapy, the risk of sharing
injecting equipment almost doubled (aOR = 1.99; 95% CI, 1.57-2.52).
“For the small subset of IDUs who continued
or resumed injecting after HAART, the odds of needle-sharing increased
approximately two-fold, with no diminution of this excess risk over > 5
years of follow-up,” note the researchers. “This indicates that for a minority
of IDUs unable to abstain from injecting, starting HIV treatment could mark a
transition to riskier injecting.”
The investigators also examined the factors
associated with continued risky behaviour after starting therapy.
They found this was associated with risky
sex in the year before treatment (OR= 3.35; 95% CI, 1.87-5.95).
Similarly, injecting drug use in the year
before treatment was associated with an eleven-fold increase in the risk of
drug during treatment (OR = 10.9; 95% CI, 6.58-17.8). Sharing injecting
equipment in the period immediately before treatment initiation more than
doubled the risk of subsequent needle sharing (OR = 2.55; 95% CI, 1.70-3.83).
The authors note that their findings differ from those of several other studies conducted in other cities, which found no increase in risky injecting behaviours.
“Our results support the optimistic view
that for most IDUs, risk compensation following HAART initiation is unlikely,
albeit with the worrisome caveat that a small minority of active injectors may
be more likely to share needles after initiating treatment,” conclude the
authors. “Based on our findings, targeting risk-reduction interventions for
persons with high-risk behaviors in the time-period shortly before HAART
initiation should be considered.”