HIV-free survival according to the early infant-feeding practices; a retrospective study in an anti-retroviral therapy programme in Makurdi, Nigeria

BACKGROUND: In Nigeria, reports of the outcomes of prevention of mother to child transmission of HIV (PMTCT) interventions had been limited to the MTCT rates of HIV, with no information on HIV-free survival (HFS) in the HIV-exposed infants over time. METHODS: A retrospective study between June 2008 and December 2011 at the Federal Medical Centre, Makurdi, Nigeria comparing HFS rates at 3 and 18 months according to the infant feeding pattern at the 6th week of life. HFS was assessed by Kaplan-Meier analysis and association of maternal and infant variables and risk of HIV acquisition or death was tested in a Cox regression analysis. RESULTS: 801 HIV uninfected infants at 6 weeks of life were studied in accordance with their reported cumulative feeding pattern. This includes 196 infants on exclusive breast feeding (EBF); 544 on exclusive breast milk substitute (EBMS) feeding and 61 on mixed feeding (MF). The overall HFS was 94.4% at 3 months and this declined significantly to 87.1% at the 18 months of age (p-value = 0.000). The infants on MF had the lowest HFS rates of 75.7% at 3 months and 69.8% at 18 months. The HFS rate for infants on EBF was 97.4% at 3 months and 92.5% at 18 month whilst infants on EBMS had HFS of 99.1% at 3 months and 86.2% at 18 months. A higher and significant drop off in HFS at the two time points occurred between infants on EBMS (12.9%) compared to infants on EBF (4.9%), p-value of 0.002, but not between infants on MF (5.9%) and EBMS, p-value of 0.114 and those on MF and EBF, p-value of 0.758. In Cox regression multivariate analyses; MF, gestational age of ˂ 37 weeks, and a high pre-delivery maternal viral load were consistently associated with HIV infection or death at 3 months and 18 months (p ˂0.05). CONCLUSION: For a better HFS in our setting; MF must be avoided, efforts to deliver babies at term in mothers with reduced viral load are advocated and EBF must be promoted as the safest and the most feasible mode of infant-feeding.