The participants were recruited from the 1242 adults
who had been taking second-line therapy for at least 24 weeks (5.5 months) and
who had previously been on first-line therapy for at least six months. The
researchers gave them two viral load tests and two resistance tests, an average
of 55 days apart.
A total of 394 people were enrolled, which was
under the target of 438, and may reflect the difficulty of patients attending
regularly enough for a clinical trial.
Their average age was 42, 60% were women, and
their average CD4 count at enrolment was 282 cells/mm3. People had
been on second-line ART for an average of 1.9 years and on first-line before
that for 2.9 years.
Boosted lopinavir was used in 94% of
second-line regimens, with the most common accompanying NRTIs being abacavir
and didanosine. This regimen, plus or minus lamivudine, was used in 52% of
people. Tenofovir was used in 19%. The most common first-line regimen had
been nevirapine, zidovudine or stavudine, and lamivudine.
Of the 394 people in the study, 203 (52%) had a viral load under 40
copies/ml, 109 (28%) had a viral load between 40 and 1000 copies/ml, and 82
(21%) had a viral load over 1000 copies/ml.
People with viral loads over 1000 copies/ml (defined
as viral failure or VF) were more likely than those who were virally suppressed
to be younger, to be taking tuberculosis treatment, to have spent less time on second-line
therapy, and to have had more days of consecutive missed therapy (treatment
interruption) on first line. Female participants were more likely to have been
People with viral loads between 40 and 1000
copies/ml (defined as low-level viraemia or LLV) were similar to those who were
virally suppressed except that, if women, they were less likely to have been
pregnant, but more likely to have first taken ART to prevent mother-to-child