Case-control study of factors associated with virologic failure in HIV-infected children on HAART in Botswana, a developing African country

According to the United Nations Program on HIV/AIDS (UNAIDS, 2008), in 2007 about 67 per cent of all HIV-infected patients in the world were in Sub-Saharan Africa, with 35% of new infections and 38% of the AIDS deaths occurring in Southern Africa. Globally, the number of children younger than 15 years of age infected with HIV increased from 1.6 million in 2001 to 2.0 million in 2007 and almost 90% of these were in Sub-Saharan Africa. (UNAIDS, 2008).^ Both clinical and laboratory monitoring of children on Highly Active Anti-Retroviral Therapy (HAART) are important and necessary to optimize outcomes. Laboratory monitoring of HIV viral load and genotype resistance testing, which are important in patient follow-up to optimize treatment success, are both generally expensive and beyond the healthcare budgets of most developing countries. This is especially true for the impoverished Sub-Saharan African nations. It is therefore important to identify those factors that are associated with virologic failure in HIV-infected Sub-Saharan African children. This will inform practitioners in these countries so that they can predict which patients are more likely to develop virologic failure and therefore target the limited laboratory monitoring budgets towards these at-risk patients. The objective of this study was to examine those factors that are associated with virologic failure in HIV-infected children taking Highly Active Anti-retroviral Therapy in Botswana, a developing Sub-Saharan African country. We examined these factors in a Case-Control study using medical records of HIV-infected children and adolescents on HAART at the Botswana-Baylor Children's Clinical Center of Excellence (BBCCCOE) in Gaborone, Botswana. Univariate and Multivariate Regression Analyses were performed to identify predictors of virologic failure in these children.^ The study population comprised of 197 cases (those with virologic failure) and 544 controls (those with virologic success) with ages ranging from 3 months to 16 years at baseline. Poor adherence (pill count <95% on at least 3 consecutive occasions) was the strongest independent predictor of virologic failure (adjusted OR = 269.97, 95% CI = 104.13 to 699.92; P < 0.001). Other independent predictors of virologic failure identified were: First Line NNRTI with Nevirapine (OR = 2.99, 95% CI = 1.19 to7.54; P = 0.020), Baseline HIV-1 Viral Load >750,000/ml (OR = 257, 95% CI = 1.47 to 8.63; P = 0.005), Positive History of PMTCT (OR = 11.65, 95% CI = 3.04-44.57; P < 0.001), Multiple Care-givers (>=3) (OR = 2.56, 95% CI = 1.06 to 6.19; P = 0.036) and Residence in a Village (OR = 2.85, 95% CI = 1.36 to 5.97; P = 0.005).^ The results of this study may help to improve virologic outcomes and reduce the costs of caring for HIV-infected children in resource-limited settings. ^ Keywords: Virologic Failure, Highly Active Anti-Retroviral Therapy, Sub-Saharan Africa, Children, Adherence.^

Determining associations and assessing methodological issues in a case-control study of hazardous air pollutants and neural tube defects

Recent studies have reported positive associations between maternal exposures to air pollutants and several adverse birth outcomes. However, there have been no assessments of the association between environmental hazardous air pollutants (HAPs) such as benzene, toluene, ethylbenzene, and xylene (BTEX) and neural tube defects (NTDs) a common and serious group of congenital malformations. Before examining this association, two important methodological questions must be addressed: (1) is maternal residential movement likely to result in exposure misclassification and (2) is it appropriate to lump defects of the neural tube, such as anencephaly and spina bifida, into a composite disease endpoint (i.e., NTDs). ^ Data from the National Birth Defects Prevention Study and Texas Birth Defects Registry were used to: (1) assess the extent to which change of residence may result in exposure misclassification when exposure is based on the address at delivery; (2) formally assess heterogeneity of the associations between known risk factors for NTDs, using polytomous logistic regression; and (3) conduct a case-control study assessing the association between ambient air levels of BTEX and the risk of NTDs among offspring. ^ Regarding maternal residential mobility, this study suggests address at delivery was not significantly different from using address at conception when assigning quartile of benzene exposure (OR 1.0, 95% CI 0.9, 1.3). On the question of effect heterogeneity among NTDs, the effect estimates for infant sex P = 0.017), maternal body mass index P = 0.016), and folate supplementation P = 0.050) were significantly different for anencephaly and spina bifida, suggesting it is often more appropriate to assess potential risk factors among subgroups of NTDs. For the main study question on the association between environmental HAPs and NTDs, mothers who have offspring with isolated spina bifida are 2.4 times likely to live in areas with the highest benzene levels (95% CI 1.1, 5.0). However, no other significant associations were observed.^ This project is the first to include not only an assessment of the relationship between environmental levels of BTEX and NTDs, but also two separate studies addressing important methodological issues associated with this question. Our results contribute to the growing body of evidence regarding air pollutant exposure and adverse birth outcomes. ^

AMERICAN TRYPANOSOMIASIS (CHAGAS') DISEASE - A STUDY OF FETO-MATERNAL MORBIDITY AND MORTALITY

The possibility of a relationship between American Trypanosomiasis (Chagas') disease and pregnancy outcome was analyzed measuring feto-maternal morbidity and mortality in a sample of 604 pregnant women and their offspring seen at the Hospital Universitario de Maternidad y Neonatologia in Cordoba, Argentina during 1979.^ A cross-sectional, "case-comparison" investigation was employed to determine the degree of risk between having a reactive chagasic serologic test and a negative pregnancy outcome as determined by abortion, stillbirth, and infant death prior to one week of age. Patients were selected using a dichotomous, 0-1 scale with either the presence or the absence of a reactive Machado-Guerreiro complement fixation serologic blood test result.^ The data obtained were analyzed using appropriate statistical techniques for measuring the comparisons between the case and control groups under various demographic and socioeconomic variables such as, age, marital status, educational attainment, and residence. Similarly, additional biological variables of birth order, maternal and fetal complications, and prematurity were examined.^ From the analysis of the data obtained in this investigation, no definite conclusions can be reached regarding the risk of having an unsuccessful pregnancy outcome in the presence of a reactive serologic finding because the study design was a cross-sectional one and the number of events were too few for an adequate analysis. Notwithstanding these limitations, the results obtained, after statistical adjustments were employed, demonstrated that women with a reactive test result were older, were of a higher parity, and were less educated. Marital status and residence were not significant variables. The risk of pregnancy wastage, however, was almost twice as frequent in the reactive group as in the non-reactive group of women. Statistically significant differences in maternal morbidity involved two complications, polyhydramnios and varicosities of the lower extremities and vulva; while in the newborn, infection was higher in infants whose mothers exhibited a reactive serologic test result.^ In summary, what this research study has shown is the need for engaging in a larger, longitudinal study for an in-depth exploration of feto-maternal morbidity and mortality--an investigation that would corraborate or refute the findings of this study.^