Comparison of percentile tables and algorithm‐based calculators for classification of blood pressures in children and adolescents with obesity: A secondary analysis of a clinical trial

AIM: Obesity as a major risk factor for childhood hypertension necessitates careful blood pressure (BP) monitoring of those affected. This study aimed to compare BP classification in a cohort of children affected by obesity using tables versus digital calculations in two sets of guidelines. METHODS: This study was a secondary analysis of data collected from a randomised clinical trial of a multidisciplinary life‐style assessment and intervention program. Baseline data from 237 children with a body mass index >99th percentile or >91st percentile with weight‐related comorbidities and available BP measurements were analysed. We assessed agreement between tables and algorithms in classification of elevated BP/pre‐hypertension and hypertension based on the American Academy of Paediatrics (AAP) clinical practice guidelines (CPG) and the older Fourth Report using Cohen's weighted kappa. The prevalence of hypertensive diagnoses was also compared between the two guidelines. RESULTS: Agreement between BP tables and algorithmic calculation of percentiles was discordant, though improved in the AAP CPG compared to the Fourth Report (Cohen's kappa = 0.70 vs. 0.57, respectively). None (0%) were missed diagnoses, and 59 (24.9%) were false positives for the Fourth Report, and 0 (0%) were missed diagnoses, and 49 (20.9%) were false positives for the AAP CPG. Under the recent guidelines, there was an increase in prevalence of 6.0% (95% confidence interval (CI) 2.5–9.4%; P = 0.0001) for BP ≥90th percentile, and of 3.0% (95% CI 0.4–5.6%; p = 0.016) for hypertension (BP ≥ 95th percentile) in the cohort (18.0% and 6.8%, respectively, increased from 12.0% and 3.8%). CONCLUSIONS: Digital calculators over tables in clinical practice are recommended where possible to improve the accuracy of paediatric BP classification. Substantial rates of elevated BP/Hypertension were found in this cohort of children and adolescents with overweight and obesity.