Effectiveness of multidrug antiretroviral regimens to prevent mother-to-child transmission of HIV-1 in routine public health services in Cameroon

Abstract

Background: Multidrug antiretroviral (ARV) regimens including HAART and short-course dual antiretroviral (sc-dARV) regimens were introduced in 2004 to improve Prevention of Mother-to-Child Transmission (PMTCT) in Cameroon. We assessed the effectiveness of these regimens from 6-10 weeks and 12 months of age, respectively.

Methodology/findings: We conducted a retrospective cohort study covering the period from October 2004 to March 2008 in a reference hospital in Cameroon. HIV-positive pregnant women with CD4 < or = 350 cells/mm(3) received first-line HAART [regimen 1] while the others received ARV prophylaxis including sc-dARV or single dose nevirapine (sd-NVP). Sc-dARV included at least two drugs according to different gestational ages: zidovudine (ZDV) from 28-32 weeks plus sd-NVP [regimen 2], ZDV and lamuvidine (3TC) from 33-36 weeks plus sd-NVP [regimen 3]. When gestational age was > or = 37 weeks, women received sd-NVP during labour [regimen 4]. Infants received sd-NVP plus ZDV and 3TC for 7 days or 30 days. Early diagnosis (6-10 weeks) was done, using b-DNA and subsequently RT-PCR. We determined early MTCT rate and associated risk factors using logistic regression. The 12-month HIV-free survival was assessed using Cox regression. Among 418 mothers, 335 (80%) received multidrug ARV regimens (1, 2, and 3) and MTCT rate with multidrug regimens was 6.6% [95%CI: 4.3-9.6] at 6 weeks, without any significant difference between regimens. Duration of mother's ARV regimen < 4 weeks [OR = 4.7, 95%CI: 1.3-17.6], mother's CD4 < 350 cells/mm(3) [OR = 6.4, 95%CI: 1.8-22.5] and low birth weight [OR = 4.0, 95%CI: 1.4-11.3] were associated with early MTCT. By 12 months, mixed feeding [HR = 8.7, 95%CI: 3.6-20.6], prematurity [HR = 2.3, 95%CI: 1.2-4.3] and low birth weight were associated with children's risk of progressing to infection or death.

Conclusions: Multidrug ARV regimens for PMTCT are feasible and effective in routine reference hospital. Early initiation of ARV during pregnancy and proper obstetrical care are essential to improve PMTCT.

Figure 1. Flowchart describing regimens received and MTCT rates at six weeks at the CNPS, Cameroon.

Between October 2004 and March 2008, 443 mother-infant pairs were eligible for the study. Among these, 25 had unexploitable data and 418 were retained for analysis.

Figure 2. Cumulative Survival rates of children by 12 month according to mode of feeding, Cameroon.

Taking in consideration defined feeding practice variables, survival curves by one year of age in each group were estimated using Kaplan Meier method. Next, survival curves between mixed-fed children (lower survival curve) and their counterpart exclusive formula-fed (middle survival curve) or exclusive breastfed (upper survival curve) were compared using the log-rank test.