Outcomes of HIV-exposed children in western Kenya: efficacy of prevention of mother to child transmission in a resource-constrained setting.

OBJECTIVES

To compare rates of mother to child transmission of HIV and infant survival in women-infant dyads receiving different interventions in a prevention of Mother to Child Transmission (pMTCT) program in western Kenya.

DESIGN

Retrospective cohort study using prospectively collected data stored in an electronic medical record system.

SETTING

Eighteen HIV clinics in western Kenya.

POPULATION

HIV-exposed infants enrolled between February 2002 and July 2007, at any of the United States Agency for International Development-Academic Model Providing Access To Healthcare partnership clinics.

MAIN OUTCOME MEASURES

Combined endpoint (CE) of infant HIV status and mortality at 3 and 18 months.

ANALYSIS

Descriptive statistics, chi Fisher exact test, and multivariable modeling.

RESULTS

Between February 2002 and July 2007, 2477 HIV-exposed children were registered for care by the United States Agency for International Development-Academic Model Providing Access To Healthcare partnership pMTCT program before 3 months of age. Median age at enrollment was 6.1 weeks; 50.4% infants were male. By 3 months, 31 of 2477 infants (1.3%) were dead and 183 (7.4%) were lost to follow-up. One thousand (40%) underwent HIV DNA Polymerase Chain Reaction virologic test at a median age of 8.3 weeks: 5% were HIV infected, 89% uninfected, and 6% were indeterminate. Of the 968 infants with specific test results or mortality data at 3 months, the CE of HIV infection or death was reached in 84 of 968 (8.7%) infants. The 3-month CE was significantly impacted (A) by maternal prophylaxis [51 of 752 (6.8%) combination antiretroviral therapy (cART); 8 of 69 (11.6%) single-dose nevirapine (sdNVP); and 25 of 147 (17%) no prophylaxis (P < 0.001)] and (B) by feeding method for the 889 of 968 (91.8%) mother-infant pairs for which feeding choice was documented [5 of 29 (17.2%) exclusive breastfeeding; 13 of 110 (11.8%) mixed feeding; and 54 of 750 (7.2%) formula feeding (P = 0.041)]. Of the 1201 infants > or = 18 months of age: 41 (3.4%) were deceased and 329 (27.4%) were lost to follow-up. Of 621 of 831 (74.7%) infants tested, 65 (10.5%) were infected resulting in a CE of 103 of 659 (15.6%). CE differed significantly by maternal prophylaxis [52 of 441 (11.8%) for cART; 13 of 96 (13.5%) for sdNVP; and 38 of 122 (31.2%) no therapy group (P < 0.001)] but not by feeding method for the 638 of 659 (96.8%) children with documented feeding choice [7 of 35 (20%) exclusive breastfeeding, 14 of 63 (22.2%) mixed, and 74 of 540 (13.7%) formula (P = 0.131)]. On multivariate analysis, sdNVP (odds ratio: 0.4; 95% confidence interval: 0.2 to 0.8) and cART (odds ratio: 0.3; 95% confidence interval: 0.2 to 0.6) were associated with fewer CE. At 18 months, feeding method was not significantly associated with the CE.

CONCLUSIONS

Though ascertainment bias is likely, results strongly suggest a benefit of antiretroviral prophylaxis in reducing infant death and HIV infection, but do not show a benefit at 18-months from the use of formula. There was a high rate of loss to follow up, and adherence to the HIV infant testing protocol was less than 50% indicating the need to address barriers related to infant HIV testing, and to improve outreach and follow-up services.