Currently recommended diagnostic threshold of hypertension by home blood pressure monitoring (HBPM) is 135/85 mmHg. However, no studies have examined the validity of recommended diagnostic threshold, using ambulatory blood pressure (ABPM) as a reference method. We compared two diagnostic threshold of HBPM 135/85 mmHg and 130/80 mmHg.Design and method:
Patients with blood pressure >=140/90 mmHg at the outpatient clinic, were enrolled. HBPM was performed for 7 days (triplicated morning and evening measurement). The 24-hour ABPM was performed on the 7th day. Among 319 patients, 256 (mean age 51.8 ± 9.7 years, 119 men) who had valid HBPM and 24-hour were analyzed. At least 5 days HBPM was averaged according European Society of Hypertension guidelines. Hypertension by 24-hour was defined as >=130/80 mmHg.Results:
The threshold 130/80 mmHg showed higher diagnostic sensitivity (90.2 vs 77.1%, p = 0.001), diagnostic agreement (84.8 vs 77.3%) and Kappa statistics (0.526 vs 0.439), compared to threshold 135/85 mmHg. Diagnostic specificity was not different. The prevalence of masked hypertension was more prevalent in threshold 135/85 mmHg compared to 130/80 mmHg (18.4 vs 7.8%, respectively, p = 0.025). The prevalence of white-coat hypertension was not different (4.3 vs 7.4%, respectively, p = 0.128).Conclusions:
Lowering of diagnostic threshold of HBPM from 135/85 mmHg to 130/80 mmHg may be better in the diagnosis of hypertension.