BMI, waist to height ratio and waist circumference as a screening tool for hypertension in hospital outpatients: a cross-sectional, non-inferiority study

OBJECTIVE: This non-inferiority study aimed to determine the burden of obesity in a hospital outpatient setting of a developing country, using three commonly employed metrics as predictors of hypertension (HTN). DESIGN: A cross-sectional study design was adopted. SETTING: This study was conducted in Health Promotion and Risk Factor Screening Services of a tertiary hospital for eye and ear, nose, throat in a semiurban area of Nepal. PARTICIPANTS: 2256 randomly selected outpatients between 40 and 69 years old. OUTCOME MEASURES: The three obesity metrics and HTN were analysed for association using correlation, the area under the receiver operating characteristic (ROC) curve and ORs. RESULTS: The prevalence of obesity or overweight by body mass index (BMI) was 58.29%; by waist-to-height ratio (WHtR) was 85.95%, high waist circumference (WC) was observed among 66.76% of participants. Female participants had a greater prevalence of high WC (77.46%) than males (53.73%) (p<0.001). Prevalence of HTN and pre-HTN were 40.67% and 36.77%, respectively. The areas under the ROC curve were significantly higher than 0.5 for BMI (0.593), WHtR (0.602) and WC (0.610). CONCLUSION: This study showed that WHtR and WC measured were not inferior to BMI as a metric for obesity detection and HTN prediction. Because of its low cost, simplicity of measurement and better ability to predict HTN, it may become a more usable metric in health facilities of low-income and middle-income countries.