Background: The diagnosis of hypertension in children is difficult because of the multiple sex-,
age-, and height-specific thresholds to define elevated blood pressure (BP). Blood pressure to height ratio (BPHR) has been proposed to facilitate the identification of elevated BP in children.
Objective: We assessed the performance of BPHR at a single screening visit to identify children with hypertension, that is, sustained elevated BP.
Method: In a school-based study conducted in Switzerland, BP was measured at up to three visits in 5207 children. Children had hypertension if BP was elevated at the three visits. Sensitivity, specificity, negative and positive predictive values (PV) for the identification of hypertension were assessed for different thresholds of BPHR. The ability of BPHR at a single screening visit to discriminate children with and without hypertension was evaluated with receiver operating characteristic (ROC) curve analyses.
Results: The prevalence of systolic/diastolic hypertension was 2.2%. Systolic BPHR had a better performance to identify hypertension compared to diastolic BPHR (area under the ROC curve: 0.95 vs. 0.84). The highest performance was obtained with a systolic BPHR threshold set at 0.80 [mmHg/cm] (sensitivity: 98%; specificity: 85%; positive PV: 12%; negative PV: 100%) and a diastolic BPHR threshold set at 0.45 [mmHg/cm] (sensitivity: 79%; specificity: 70%; positive PV: 5%; negative PV: 99%). The positive PV was higher among tall or overweight children.
Conclusion: BPHR at a single screening visit had a high performance to identify hypertension in children, although the low prevalence of hypertension led to a low positive PV.