Peripartum nevirapine exposure and subsequent clinical outcomes among HIV-infected women receiving antiretroviral therapy for at least 12 months.

OBJECTIVE: Prior exposure to intrapartum/neonatal nevirapine (NVP) is associated with compromised virologic treatment outcomes once non-nucleoside reverse transcriptase inhibitor (NNRTI)-based antiretroviral therapy (ART) is initiated. We examined the longer-term clinical outcomes in a programmatic setting.
METHODS: We compared post-12 month mortality and clinical treatment failure (defined by WHO clinical and immunologic criteria) among women with and without prior NVP exposure in Lusaka, Zambia.
RESULTS: Between April 2004 and July 2006, 6740 women initiated an NNRTI-containing regimen. At 12 months, 5172 (78%) remained active and were included in this analysis. Of these, 596 (12%) reported prior NVP exposure, whose time from exposure to ART initiation was: <6 months for 11%, 6-12 months for 13%, >12 months for 37%, unknown for 39%. Overall, women with prior NVP exposure trended towards increased survival (adjusted hazard ratio [AHR]: 0.53; 95% confidence interval [CI]: 0.27-1.06, P = 0.07) and towards increased hazard of clinical treatment failure (AHR: 1.18; 95% CI: 0.95-1.47, P = 0.14), particularly those with exposure for <6 months (AHR: 1.52; 95% CI: 0.94-2.45, P = 0.09).
CONCLUSIONS: Prior NVP exposure appeared to increase risk for clinical treatment failure after 12 months of follow-up, but this finding did not reach statistical significance. With growing evidence linking recent NVP exposure to virologic failure, optimized monitoring algorithms should be considered for women with starting NNRTI-based ART. The association between prior NVP exposure and improved survival has not been previously shown and may be a result of residual confounding around health-seeking behaviours.