Nonvirologic algorithms for predicting HIV infection among HIV-exposed infants younger than 12 weeks of age.

BACKGROUND: Early initiation of antiretroviral therapy has been shown to reduce mortality among perinatally HIV-infected infants, but availability of virologic testing remains limited in many settings. METHODS: We collected cross-sectional data from mother-infant pairs in three primary care clinics in Lusaka, Zambia, to develop predictive models for HIV infection among infants younger than 12 weeks of age. We evaluated algorithm performance for all possible combinations of selected characteristics using an iterative approach. In primary analysis, we identified the model with the highest combined sensitivity and specificity. RESULTS: Between July 2009 and May 2011, 822 eligible HIV-infected mothers and their HIV-exposed infants were enrolled; of these, 44 (5.4%) infants had HIV diagnosed. We evaluated 382,155,260 different characteristic combinations for predicting infant HIV infection. The algorithm with the highest combined sensitivity and specificity required 5 of the following 7 characteristic thresholds: infant CD8 percentage >22; infant CD4 percentage ≤44; infant weight-for-age Z score ≤0; infant CD4 ≤1600 cells/µL; infant CD8 >2200 cells/µL; maternal CD4 ≤600 cells/µL; and mother not currently using antiretroviral therapy for HIV treatment. This combination had a sensitivity of 90.3%, specificity of 78.4%, positive predictive value of 22.4%, negative predictive value of 99.2% and area under the curve of 0.844. CONCLUSION: Predicting HIV infection in HIV-exposed infants in this age group is difficult using clinical and immunologic characteristics. Expansion of polymerase chain reaction capacity in resource-limited settings remains urgently needed.

Association between weight gain and clinical outcomes among malnourished adults initiating antiretroviral therapy in Lusaka, Zambia.

OBJECTIVE: To describe the association between 6-month weight gain on antiretroviral therapy (ART) and subsequent clinical outcomes. DESIGN: A retrospective analysis of a large programmatic cohort in Lusaka, Zambia. METHODS: Using Kaplan-Meier analysis and Cox proportional hazards models, we examined the association between 6-month weight gain and the risk of subsequent death and clinical treatment failure. Because it is a known effect modifier, we stratified our analysis according to body mass index (BMI). RESULTS: Twenty-seven thousand nine hundred fifteen adults initiating ART were included in the analysis. Patients in the lower BMI categories demonstrated greater weight gain. In the post 6-month analysis, absolute weight loss was strongly associated with mortality across all BMI strata, with the highest risk observed among those with BMI <16 kg/m (adjusted hazard ratio 9.7; 95% CI: 4.7 to 20.0). There seemed to be an inverse relationship between weight gain and mortality among patients with BMI <16 kg/m. Similar trends were observed with clinical treatment failure. CONCLUSIONS: Weight gain after ART initiation is associated with improved survival and decreased risk for clinical failure, especially in the lower BMI strata. Prospective trials to promote weight gain after ART initiation among malnourished patients in resource-constrained settings are warranted.

Early immunologic response and subsequent survival among malnourished adults receiving antiretroviral therapy in Urban Zambia.

OBJECTIVE: To evaluate the relationship between early CD4(+) lymphocyte recovery on antiretroviral therapy (ART) and subsequent survival among low body mass index (BMI) HIV-1-infected adults. DESIGN: Retrospective analysis of a large programmatic cohort in Lusaka, Zambia. METHODS: We evaluated ART-treated adults enrolled in care for more than 6 months. We stratified this study population according to World Health Organization (WHO) malnutrition criteria: normal (BMI >or=18.5 kg/m(2)), mild (17.00-18.49), moderate (16.00-16.99), and severe (<16.0). We used Cox proportional hazards regression to estimate the subsequent risk of death associated with absolute CD4(+) cell count change over the first 6 months on ART. To account for effect modification associated with baseline CD4(+) cell count, a weighted summary measure was calculated. RESULTS: From May 2004 to February 2009, 56,612 patients initiated ART at Lusaka district clinics; of these, 33 097 (58%) were included in this analysis. The median change in 0-6 month CD4(+) cell count in each baseline BMI strata varied from 127 to 131 cells/microl. There was a statistically significant, inverse association between baseline BMI and the post 6-month hazard for mortality only among those patients with less than 100 cells/microl increase in the first 6 months of ART. A CD4(+) cell count increase of at least 100 cells/microl over the first 6 months of ART was not associated with a higher hazard for mortality, regardless of baseline BMI. CONCLUSIONS: Low baseline BMI and attenuated CD4(+) cell count response at 6 months had a compounding, negative impact on post 6-month survival. Specific guidelines for monitoring ART response using immunologic criteria may be warranted for low BMI patients.