Abstract:
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, x2 Fisher exact test, and multivari-
able 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 $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.