Measuring and correcting biased child mortality statistics in countries with generalized epidemics of HIV infection.

OBJECTIVE: Under Millennium Development Goal 4, countries are required to reduce child mortality by two-thirds between 1990 and 2015. In countries with generalized epidemics of human immunodeficiency virus (HIV) infection, standard statistics based on fertility history may misrepresent progress towards this target owing to the correlation between deaths among mothers and early childhood deaths from acquired immunodeficiency syndrome. METHODS: To empirically estimate this bias, child mortality data and fertility history, including births to deceased women, were collected through prospective household surveys in eastern Zimbabwe during 1998-2005. A mathematical model was then used to investigate the determinants and temporal dynamics of the bias, first in Zimbabwe and then in other countries with different background mortality rates and HIV-related epidemic profiles. FINDINGS: According to the empirical data, standard cross-sectional survey statistics underestimated true infant and under-5 mortality by 6.7% and 9.8%, respectively. These estimates were in agreement with the output from the model, in which the bias varied according to the magnitude and stage of the epidemic of HIV infection and background mortality rates. The bias was greater the longer the period elapsed before the survey and in later stages of the epidemic. Bias could substantially distort the measured effect of interventions to reduce non-HIV-related mortality and of programmes to prevent mother-to-child transmission, especially when trends are based on data from a single survey. CONCLUSION: The correlation between the HIV-related deaths of mothers and their children can bias survey estimates of early child mortality. A mathematical model with a user-friendly interface is available to correct for this bias when measuring progress towards Millennium Development Goal 4 in countries with generalized epidemics of HIV infection.

Changing patterns of adult mortality as the HIV epidemic matures in Manicaland, eastern Zimbabwe.

BACKGROUND: HIV prevalence declined in Manicaland, eastern Zimbabwe, between 1998 and 2003. During this period, adult mortality in men was stable, whereas female mortality increased to levels similar to those of men. We examine the trends in mortality from 2003 to 2005. METHODS: A population-based cohort was recruited from a household census in 12 communities. A baseline survey was conducted between 1998 and 2000, with the first and second follow-up surveys occurring after 3 and 5 years, respectively. Using checklists of the resident population at the previous round, adult deaths were reported to enumerators by surviving household members or community informants. RESULTS: Age-standardized adult mortality rates for men increased slightly but not significantly over time (1998-2000: 24/1000 person-years; 2001-2002: 26/1000 person-years; 2003-2005: 31/1000 person-years), reflecting a sharp rise in mortality among HIV-positive individuals (62, 79 and 105 per 1000 person-years). Female mortality rose sharply initially but levelled off after 2001 (15, 26 and 26 per 1000 person-years) also caused by the pronounced increase in mortality among HIV-positive women (35, 75 and 88/1000 person-years; 7/1000 person-years for HIV-negative men and women in all periods); 69% of adult male deaths and 74% of adult female deaths were attributable to HIV/AIDS in 2003-2005. In men, mortality was similar and stable in towns, estates, roadside business centres and subsistence farming areas. In women, mortality rose in towns and subsistence farming areas between 1998 and 2002 and was greater in towns than in other locations. CONCLUSION: Recent data indicate that adult mortality may be stabilizing in eastern Zimbabwe after the recent downturn in HIV prevalence.