Associations and Discriminatory Performance of Anthropometric and Body-Shape Indices for Identifying Hypertension in Adults with Type 2 Diabetes in Malawi: A Cross-Sectional Study

Background: We evaluated the discriminatory performance of traditional anthropometric parameters and novel body-shape indices for identifying hypertension among adults with type 2 diabetes mellitus (T2DM) in Malawi. Methods: This was a multicenter cross-sectional study of 1356 adults with T2DM attending outpatient diabetes clinics at three tertiary referral hospitals. Traditional anthropometric parameters were body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR). Novel body-shape indices were the weight-adjusted waist index (WWI), a body shape index (ABSI), the conicity index, and body roundness index (BRI). Hypertension was defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg, or current antihypertensive medication use. Multivariable logistic regressions and receiver operating characteristic (ROC) analyses were performed overall and, as secondary subgroup analyses, stratified by sex; effect modification by sex was tested formally using interaction terms. Results: Overall, 68.3% had hypertension. All anthropometric measures were positively associated with hypertension in adjusted models. The strongest associations were observed for WHtR and its monotonic transformation, the BRI (aOR, 1.79; 95% CI 1.55–2.07 and aOR, 1.80; 95% CI 1.55–2.09, respectively), followed by WC (aOR, 1.70; 95% CI 1.48–1.95). The ranking of measures was similar in men and women, and no measure showed a statistically significant sex interaction. WHtR and BRI had the highest overall AUCs (0.69; 95% CI 0.66–0.72), followed by WC (0.68; 95% CI 0.65–0.71), indicating modest discrimination. Youden-derived WHtR cut-offs were 0.53 in men and 0.61 in women. Conclusions: All anthropometric measures were independently associated with hypertension, but discrimination was modest and none are adequate as a stand-alone screening test. WHtR is the simplest of the best-performing measures and may help prioritize patients for repeat blood pressure assessment in resource-limited diabetes clinics. The sex-stratified estimates and the internally derived cut-offs are exploratory and require external validation.