Reassessing home blood pressure thresholds: clinical implications of lowering the diagnostic criteria to 130/80 mmHg

Objectives: This study investigated whether lowering the home blood pressure (BP) threshold for the diagnosis of hypertension from 135/85 to 130/80 mmHg enhances diagnostic accuracy when assessed against ambulatory BP monitoring (ABPM). Methods: A total of 646 untreated participants (mean age 52 ± 10 years; 310 men) with valid 3-day office BP, 7-day home BP, and 24-h ABPM data and preserved renal function were included. Hypertension phenotypes were classified as normotension, white-coat, masked, and sustained hypertension according to office BP and ABPM criteria. Results: Lowering the home BP threshold increased sensitivity from 72.3 to 89.5% but reduced specificity from 81.8 to 69.1%, thereby improving overall diagnostic accuracy from 73.1 to 87.8% and the kappa coefficient from 0.238 to 0.247. At the conventional threshold of 135/85 mmHg, 63.2% of masked and 15.1% of sustained hypertension were misclassified as normotension, whereas these rates declined to 30.3 and 3.4%, respectively, at the 130/80 mmHg threshold. Individuals with home BP between 130/80 and 134/84 mmHg showed intermediate office and ambulatory BP values, with a high prevalence of masked (32.9%) and sustained hypertension (11.7%). Within this subgroup, isolated nighttime and daytime–nighttime hypertension were identified in 35.7 and 13.5% of participants, respectively. Conclusion: The conventional home BP threshold of 135/85 mmHg may fail to identify a considerable proportion of masked, sustained, and nighttime hypertension. Lowering the threshold to 130/80 mmHg, or designating 130/80–134/84 mmHg as a diagnostic ‘gray zone’ warranting ABPM confirmation, may improve diagnostic precision and facilitate earlier detection of hypertension in clinical practice.