Comparison of Optimal Diagnostic Thresholds of Hypertension With Home Blood Pressure Monitoring and 24-Hour Ambulatory Blood Pressure Monitoring

BACKGROUND Differences between the recently suggested outcome-driven diagnostic threshold of home blood pressure (HBP) measurements and the currently recommended diagnostic threshold of HBP measurements may cause a disagreement between 24-hour ambulatory blood pressure (ABP) and HBP measurements in the diagnosis of hypertension. We evaluated the agreement of various HBP diagnostic thresholds (135/85, 130/85, and 130/80 mm Hg) to ABP measurements, as a reference method. METHODS Patients who were confirmed to have high BP (>= 140/90 mm Hg) at the outpatient clinic were referred. HBP measurement was performed for 7 days in triplicates every morning and evening. The 24-hour ABP measurement was performed on the 8th day. Using 24-hour ABP measurement as a reference method, we analyzed HBP diagnostic thresholds at 135/85, 130/85, and 130/80 mm Hg. RESULTS Among 319 patients, 256 patients (mean age, 51.8 +/- 9.7 years; 119 men) with valid HBP measurements and 24-hour ABP measurements were enrolled. The threshold of 130/80 mm Hg showed the highest diagnostic sensitivity (P = 0.001) with diagnostic agreement by Kappa statistics. Using 130/80 mm Hg as a diagnostic threshold of hypertension, the prevalence of masked hypertension was significantly lower than 130/85 and 135/85 mm Hg (7.8, 15.2, and 18.4%, respectively, P = 0.002). CONCLUSIONS The present study suggests that lowering the diagnostic thresholds of HBP measurement from 135/85 mm Hg to 130/80 mm Hg may improve diagnostic accuracy for hypertension.