Blood pressure to height ratios as simple, sensitive and specific diagnostic tools for adolescent (pre)hypertension in Nigeria

BACKGROUND The age-, gender-, and height-percentile requirements of the 'gold-standard' for the diagnosis of (pre)hypertension in adolescents make it time-consuming for clinicians and difficult-to-use by non-professionals. Simplified diagnostic tools are therefore needed. The use of blood pressure-to-height ratio (BPHR)--systolic BPHR (SBPHR) and diastolic BPHR (DBPHR)--has been reported in Han adolescents, but it requires validation in other racial groups. The diagnostic accuracy of SBPHR and DBPHR in a population of 1,173 Nigerian adolescents aged 11-17 years, was therefore studied. METHODS Blood pressures were measured using standard procedures and (pre)hypertension were defined according to international recommendations. ROC curve analyses were used to assess the diagnostic accuracy of BPHR in defining (pre)hypertension in this population. Sex-specific threshold values for SBPHR and DBPHR were determined, and thereafter used to define (pre)hypertension. The sensitivity/specificity of this method was determined. RESULTS The accuracies of SBPHR and DBPHR in diagnosing (pre)hypertension, in both sexes, was > 92%. The optimal thresholds for diagnosing prehypertension were 0.72/0.46 in boys and 0.73/0.48 in girls; while for hypertension, they were 0.75/0.51 in boys and 0.77/0.50 in girls. The sensitivity and specificity of this method were > 96%. CONCLUSIONS The use of BPHR is valid, simple and accurate in this population. Race-specific thresholds are however needed.