Diagnostic Performance of Obesity Indices for Predicting Hypertension Among Children Aged 6–13 Years in Polokwane: A ROC Analysis

ABTRACT Objective The increasing prevalence of childhood hypertension in South Africa and other low- and middle-income countries is a pressing public health issue. As urbanization progresses and lifestyle changes occur, children are exposed to heightened cardiometabolic risks. The aim of the study was to evaluate and compare the predictive ability of multiple anthropometric indices in detecting hypertension among private school children aged 6 to 13 years. Methods A total of 1,665 learners (821 boys and 808 girls), aged 6 to 13 years, participated in a cross-sectional survey conducted across three private schools in Polokwane, Limpopo Province, South Africa. All anthropometric measurements were taken according to standard procedures of the International Society for the Advancement of Kinanthropometry. The Mann–Whitney U test and receiver operating characteristic curve analysis were performed using R software version 4.4.1. Results Hypertensive children were significantly older than their non-hypertensive peers (10.77 ± 1.89 vs 9.82 ± 2.12 years; p < 0.001). Among boys, the body roundness index showed higher predictive accuracy than a body shape index, conicity index, and weight-adjusted waist index, whereas among girls, a body shape index outperformed body roundness index, conicity index, and weight-adjusted waist index, indicating gender differences in discriminatory power. Overall, waist circumference and body mass index demonstrated the strongest performance in both sexes (area under the curve greater than 0.650), reflecting fair to good accuracy. Conclusions Waist circumference and body mass index, which demonstrated the strongest overall predictive performance, should be incorporated into routine school-based and primary healthcare screening programmes as cost-effective tools for early identification of children at risk of hypertension.