Performance of modified blood pressure-to-height ratio for diagnosis of hypertension in children: The CASPIAN-V study

This study aimed to evaluate the accuracy and performance of modified blood pressure-to-height ratio (MBPHR) for identifying high blood pressure (HBP) in a large population of children. This multicentric cross-sectional study was conducted on a nationally representative sample of 7349 Iranian students aged 7-12 years living in 30 provinces in Iran. High systolic blood pressure and diastolic blood pressure were defined according to the 2017 American Academy of Pediatrics (AAP) guidelines. The BP-to height ratio (BPHR) was calculated as BP (mmHg)/height (cm), MBPHR3 as BP (mmHg)/(height (cm) + 3 (13-age)), and MBPHR7 as BP (mmHg)/(height (cm) + 7 (13-age). The receiver-operating characteristic curve analysis was used to evaluate the performance of these three ratios for identification of HBP in children compared to the 2017 AAP guidelines as the gold standard. Mean age of participants was 12.29 +/- 3.15 years and 3736 (50.8%) were girls. The prevalence of HBP was 11.9% (11.5% in boys, 12.3% in girls). The area under the curve (AUC) was higher for MSBPHR3/MDBPHR3 (0.97/0.98) than MSBPHR7/MDBPHR7 (0.96/0.97) and SBPHR/DBPHR (0.96/0.95) for identifying high Systolic and diastolic BP. The optimal cut-off points for MSBPHR3/MDBPH, MSBPHR7/MDBPHR7, and SBPHR/DBPHR were 0.76/0.50, 0.69/0.46, and 0.81/0.52 respectively. Negative predictive value was nearly perfect for three ratios (>= 98%). Positive predictive value was higher for MBPHR3 (52.7%) than MBPHR7 (51.0%) and BPHR (39.8%). Overall, MBPHR3 had better performance than MBPHR7 and BPHR for identification of HBP in Iranian children and it may improve early hypertension recognition and control in primary screening.