title: Estimating the efficacy of interventions to prevent mother-to-child transmission of human immunodeficiency virus in breastfeeding populations: comparing statistical methods.
abstract: Postnatal transmission of human immunodeficiency virus infection through breastfeeding complicates evaluating the efficacy of interventions aimed to reduce mother-to-child transmission risk. Results from trials in Africa evaluating either peripartum antiretroviral therapy or refraining from breastfeeding show an estimated long-term efficacy at 15-24 months of age between 25 and 50 percent. Differences in statistical methods, duration of follow-up, and age at weaning hinder direct comparison between trials. The authors recently outlined theoretically preferred statistical methods for evaluating interventions aimed to reduce risk of mother-to-child transmission of human immunodeficiency virus. When multiple test results and/or supplementary information is available, the more sophisticated methods account for the fact that exact age at infection is unknown, that risk for infection ends at weaning, or that censoring due to death may be informative. The authors apply these methods to four scenarios, using data from four randomized trials carried out in Africa between 1995 and 2000. The authors' findings suggest that, to estimate the cumulative proportion infected at age 6 weeks, a standard Kaplan-Meier approach is likely to give valid results. For estimation of this proportion at age 18 months, more sophisticated methods, such as the extension of the Kaplan-Meier procedure to interval-censored data and competing risks, would be preferred.
authors.affiliation: INSERM U. 593, Institut d'Epidémiologie, Santé Publique et Développement, Université Victor Segalen Bordeaux 2, Bordeaux, France.
authors.forename: Ahmadou
authors.initials: A
authors.lastname: Alioum
authors.forename: Mario
authors.initials: M
authors.lastname: Cortina-Borja
authors.forename: François
authors.initials: F
authors.lastname: Dabis
authors.forename: Laurence
authors.initials: L
authors.lastname: Dequae-Merchadou
authors.forename: Geert
authors.initials: G
authors.lastname: Haverkamp
authors.forename: James
authors.initials: J
authors.lastname: Hughes
authors.forename: John
authors.initials: J
authors.lastname: Karon
authors.forename: Valeriane
authors.initials: V
authors.lastname: Leroy
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Newell
authors.forename: Barbra A
authors.initials: BA
authors.lastname: Richardson
authors.forename: Liesbeth
authors.initials: L
authors.lastname: van Weert
authors.forename: Gerrit-Jan
authors.initials: GJ
authors.lastname: Weverling
mesh_terms: D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use; D001942:Breast Feeding / Q000009:adverse effects*; D005260:Female; D015658:HIV Infections; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control*; D008895:Milk, Human / Q000821:virology*; D011247:Pregnancy; D016032:Randomized Controlled Trials as Topic; D013223:Statistics as Topic / Q000379:methods*
chemical_list: D000998:Antiviral Agents