Studies indicate when HIV therapy should start
Decisions about when to initiate antiretroviral therapy in children and adults infected with HIV will be informed by data from two studies published earlier this week.
The first, a meta-analysis of data from 3,941 children, indicates that
in older children CD4 count and viral load can be used as markers to
predict whether therapy can be safely deferred. For children under one
year, however, such markers do not predict risk for progression. The
researchers, led by Dr David Dunn of the Medical Research Council Clinical
Trials Unit, London, suggest that this finding lends support to a universal
treatment policy for infants (Lancet 2003;362:1605).
However, the authors of an accompanying editorial point out that such
a policy would prematurely expose many children to avoidable toxic effects,
the burden of strict adherence and the risk of developing resistance.
They also ask whether such a recommendation would commit all HIV-infected
children to lifelong therapy from birth. “Or is it feasible to
treat children when they are most vulnerable and then to stop treatment
at a safer time,” they ask (ibid, p1595).
The second study, published in Annals of Internal Medicine (2003;139:810),
shows that adherence to antiretroviral regimens is the critical determinant
of survival for patients infected with HIV, not the CD4 cell count when
therapy is begun.
Dr Evan Wood and colleagues from St Paul’s Hospital and the University
of British Columbia, Vancouver, examined how well patients adhered to
highly active antiretroviral therapy (HAART) during their first year
of treatment and then reviewed medical records to assess deaths that
occurred during the subsequent five-year period.
They found that, among patients who adhered to treatment, survival was
similar regardless of whether therapy was started when CD4 cells counts
were 200 to 349 cells/mm3 or higher. They also found that patient non-adherence
was strongly associated with mortality, even among patients who began
HAART when their CD4 cell count was relatively high.
The researchers point out that the optimal timing of HAART initiation
is a critical clinical question. “Patients must balance the risks
for disease progression or diminished effectiveness of HAART with premature
drug resistance, side effects and potentially life-threatening toxicities.” They
suggest that HAART may be safely delayed until a CD4 cell count of 200
cells/mm3 is reached. “Earlier treatment initiation does not protect
against the deleterious effects of non-adherence,” they conclude. |
