Abstract:
BACKGROUND : We aimed to develop and validate a tool to identify which pregnant/lactating young South African
women (≤ 24 years) are at risk of HIV infection.
METHODS : Data from three national South African Prevention of Mother-to-Child Transmission (PMTCT) evaluations
were used to internally validate three HIV acquisition risk models for young postpartum women. We used univariate
and multivariable logistic regression analysis to determine which risk factors were significant. Model coefficients were
rounded and stratified into risk groups and the area under the receiver operating curve (AUROC) was computed.
Models were developed to determine which risk factors provided the most predictive accuracy whilst remining clinically
meaningful.
RESULTS : Data from 9 456 adult and 4 658 young pregnant and lactating women were included in the development
and validation data sets, respectively. The optimal model included the following risk factors: age (20–24 years old),
informal house structure, two or more pregnancies, mothers who had knowledge of when they received their last HIV
test result, no knowledge of the infant’s father’s HIV status, no knowledge of breastfeeding as a mode of MTCT and
knowledge of PMTCT programme. The mean AUROC was 0.71 and 0.72 in the development and validation datasets
respectively. The optimum cut off score was ≥ 27, having 84% sensitivity, 44% specificity, and identifying 44% of highrisk
women eligible for PrEP.
CONCLUSION : The optimal model to be used as a possible risk scoring tool to allow for early identification of those
pregnant/lactating women most at-risk of HIV acquisition included both statistically as well as clinically meaningful
risk factors. A field-based study is needed to test and validate the effectiveness of this targeted approach.
