Meta-analysis of two randomized controlled trials comparing combined zidovudine and didanosine therapy with combined zidovudine, didanosine, and nevirapine therapy in patients with HIV
Jm. Raboud et al., Meta-analysis of two randomized controlled trials comparing combined zidovudine and didanosine therapy with combined zidovudine, didanosine, and nevirapine therapy in patients with HIV, J ACQ IMM D, 22(3), 1999, pp. 260-266
Objectives: To extend the range of CD4 counts in which a plasma viral load
nadir (pVL) <20 copies/ml was known to be predictive of the duration of vir
ologic response. To determine whether baseline pVL is predictive of virolog
ic response during the study periods.
Methods: A meta-analysis was conducted of the original individual patient d
ata from two randomized controlled trials comparing zidovudine (ZDV)/didano
sine (ddI) with ZDV/ddI/nevirapine (NVP).
Results: In total, 87 patients received ZDV/ddI and 83 received ZDV/ddI/NVP
. Study subjects on triple therapy with baseline gVL <100,000 copies/ml wer
e more likely to achieve a pVL <300 copies/ml (odds ratio [OR] = 2.49; p =
.02) and <20 copies/ml (OR = 4.76; p = .001) during the trial than those wi
th baseline pVL >100,000 copies/ml. Among triple therapy patients, the rela
tive risk of virologic failure was higher for patients with higher baseline
pVL (rate ratio [RR] = 2.51/log(10) copies/ml, p = .01), after controlling
for compliance and pVL nadir. The relative risks of virologic failure asso
ciated with pVL nadir <20 copies/ml and between 21 and 400 copies/ml were .
04 (p = .0001) and .56 (p = .26), respectively, compared with patients with
a pVL nadir >400 copies/ml.
Conclusions: We have extended our earlier results that achieving a pVL nadi
r <20 copies/ml is important for maintaining virologic suppression. In part
icular, we have demonstrated that a pVL nadir <20 copies/ml is at least fiv
efold more protective against virologic failure than achieving a pVL nadir
between 20 and 400 copies/ml. Baseline pVL is significantly associated with
the probability of achieving and sustaining virologic suppression.