Survival from 9 months of age among HIV-infected and uninfected Zambian children prior to the availability of antiretroviral therapy

Abstract

Background: Few prospective studies have measured survival rates among human immunodeficiency virus (HIV)-infected children in sub-Saharan Africa prior to the availability of antiretroviral therapy.

Methods: In the context of an observational study of the immunogenicity of measles vaccine in Zambia, we prospectively followed up children from approximately 9 months of age and assessed survival rates, risk factors for mortality, and circumstances at the time of death according to HIV-infection or HIV-exposure status.

Results: There were 56 deaths among 492 study children during follow-up to 3 years of age. Thirty-nine percent of the 105 children with HIV infection died during the study period, compared with 5.0% of the 260 HIV-seropositive but uninfected children and 1.6% of the 127 HIV-seronegative children. Estimated survival probabilities from 9 through 36 months of age were 52% among HIV-infected children, 95% among initially HIV-seropositive but uninfected children, and 98% among HIV-seronegative children. In multivariable analyses, history of a clinic visit within the 4 weeks prior to study entry (adjusted hazard ratio, 4.6; 95% confidence interval, 1.5-13.5), hemoglobin level <8 g/dL at study entry (adjusted hazard ratio, 4.4; 95% confidence interval, 1.5-12.6), and CD4(+) T lymphocyte percentage <15% at study entry (adjusted hazard ratio, 3.2; 95% confidence interval, 1.1-9.5) were associated with mortality among HIV-infected children.

Conclusions: Only approximately one-half of HIV-infected Zambian children who were alive at 9 months of age survived to 3 years of age, supporting the urgent need for the prevention of mother-to-child transmission of HIV and the early diagnosis and treatment of HIV infection in children in sub-Saharan Africa.

Figure 1

Study profile examining survival from 9 months of age among HIV-infected and uninfected Zambian children prior to the availability of antiretroviral therapy. ^aThirty-three vaccinated children missed the scheduled visit at 1 month but returned at 3 months; 1 child missed the 1-month, 3-month, and 2-year visits but returned at 3 years. ^bFour children who returned at the 1-month visit missed the 3-month visit but returned at 2 years, and 1 child missed both the 3-month and 2-year visits but returned at 3 years. ^cEleven children who returned at the 3-month visit missed the 2-year visit but returned at 3 years. ^dIncludes 86 children traced by a community health worker at home and determined to be alive at the end of scheduled the follow-up period. FU, follow-up.

Figure 2

Kaplan-Meier survival curves by HIV exposure and infection status. P < .001, by log-rank test for differences between groups.

Figure 3

Venn diagrams showing distributions and overlap of the 3 most common illnesses contributing to death (diarrhea, acute respiratory infection [ARI], and malnutrition) for HIV-uninfected children and HIV-infected children.