Home versus ambulatory blood pressure monitoring in the diagnosis of clinic resistant and true resistant hypertension

Ambulatory blood pressure (ABP) monitoring is recommended as a standard method for the evaluation of resistant hypertension (RH). This study assessed the diagnostic value of home blood pressure (HBP) monitoring in RH. Subjects on stable treatment with ⩾3 antihypertensive drugs were included. Clinic RH (CRH) was defined as elevated clinic blood pressure and true RH (TRH) as elevated ABP. The diagnosis of CRH was verified by ABP and HBP monitoring. The diagnostic value of HBP was assessed by taking ABP as reference method. Threshold for hypertension diagnosis was ⩾135/85 mm Hg (systolic and/or diastolic) for HBP and awake ABP and ⩾140/90 mm Hg for clinic blood pressure. Among 73 subjects on ⩾3 antihypertensive drugs, 44 (60%) had CRH and 40 (55%) TRH. There was agreement between ABP and HBP in diagnosing CRH in 82% of the cases (26 subjects (59%) with CRH and 10 (23%) without CRH; kappa 0.59). Regarding the diagnosis of TRH, there was agreement between ABP and HBP in 74% of the cases (36 subjects (49%) with TRH and 18 (25%) without TRH; kappa 0.46). The sensitivity, specificity, and positive and negative predictive values of HBP in detecting CRH were 93%, 63%, and 81% and 83%, respectively, and TRH were 90%, 55%, and 71%, and 82%, respectively (ABP taken as reference method). These data suggest that HBP is a reliable alternative to ABP in the evaluation of RH. These methods are necessary in both uncontrolled and controlled subjects on triple therapy to detect the white coat phenomenon and also masked RH.