Measuring and Correcting Biased Child Mortality Statistics in Countries with Generalized Epidemics of HIV infection/Mesure et Correction Des Erreurs De Statistiques En Termes De Mortalite Infantile Dans Les Pays Presentant Une Epidemie Generalisee D'infection Au VIH/Medicion Y Correccion De Los Datos Estadisticos Sesgados Sobre Mortalidad Infantil En Paises Con Epidemia

Introduction Millennium Development Goal 4 (MDG4) calls for countries to reduce child mortality rates by two-thirds between 1990 and 2015. (1,2) There is concern that progress towards meeting this target in subSaharan African countries with generalized epidemics of human immunodeficiency-virus (HIV) infection is being hampered directly by high levels of mother-to-child HIV transmission, and indirectly by illness and death among mothers with acquired immunodeficiency syndrome (AIDS), both of which undermine children's care. (3-6) According to the Joint United Nations Programme for HIV/AIDS (UNAIDS), in the 1990s HIV infection and AIDS accounted for more than 20% of the total risk of dying before the age of 5 years in seven countries. (7) However, the subsequent scale-up of antiretroviral therapy (ART) programmes and of national interventions to prevent mother-to-child HIV transmission (8,9) offers hope that HIV/AIDS control programmes can help meet the international goal. To establish whether MDG4 is met, improved methods are being developed to measure trends in child mortality, which are usually assessed by interviewing mothers about the survival of their children, (10-13) In many countries there have been sustained declines in childhood mortality since 1950, but in some of the countries with severe epidemics of HIV infection, paediatric AIDS has generated increases in recent years. (13) Unfortunately, estimates of infant and under-5 mortality rates in countries experiencing generalized HIV epidemics are subject to important bias (10,14) that could lead to an incorrect assessment of their progress towards attaining MDG4. The bias stems from the fact that deaths occur most often in children born to women infected with HIV, who are less likely to be included in surveys because of illness or death. Little headway has been made in addressing this bias, whose magnitude is hard to estimate because it is determined by a set of inter-dependent relationships between fertility, mother's age, stage of HIV infection, the risk of mother-to-child transmission and the survival of infected children. Such bias could be important in cross-country comparisons because it may vary according to the level of non-AIDS-related background mortality, as well as with the magnitude and stage of the epidemic of HIV infection. It could also confound trends analyses because its magnitude may change as the epidemic evolves, owing to changes in the age pattern of HIV infection, the number of women with advanced disease, and the uptake of services for the prevention of mother-to-child transmission and for the delivery of ART. In this study we have tested the hypothesis that the correlation between death from HIV infection in mothers and their young children can cause a bias in child mortality rate estimates in excess of 5% (a level judged to introduce serious error). (15) To test this hypothesis we drew upon childhood mortality data from a prospective population-based cohort study in Zimbabwe whose data covered both children born to women who were still living and children whose mothers had died. We developed a mathematical model to produce estimates of the bias in national surveys, first in Zimbabwe and then in other selected countries with different epidemic profiles of HIV infection and different baseline infant and childhood mortality rates. The model can be used to derive corrected infant and under-5 mortality rates and their trends for countries with generalized epidemics of HIV infection. Methods Data and analysis The data used in this analysis were taken from the Manicaland HIV/STD Prevention Study in eastern Zimbabwe. The detailed procedures followed in the study have been published elsewhere. (16) In brief, between July 1998 and February 2000 we conducted a baseline census of households in 12 locations in a phased manner (one site at a time) and recruited into an open cohort a random sample of adult household residents. …