IS HOME BLOOD PRESSURE MONITORING USEFUL IN THE DIAGNOSIS AND MANAGEMENT OF REFRACTORY HYPERTENSION?

Abstract

Objective: Refractory hypertension (RefHT) is defined as uncontrolled blood pressure (BP) despite the use of 5 or more antihypertensives including a long-acting thiazide diuretic and a mineralocorticoid receptor antagonist. It is a subgroup of resistant hypertension (RHT) with recent definition and behavior of extreme severity and refractoriness to treatment. Among resistant hypertensives, the use of ABPM is mandatory, and it has already been shown that HBPM is a good alternative in the follow-up of these patients. Design and method: Cross-sectional study of a historical cohort of patients with RHT. A total of 354 patients (23.9% male; mean age 60.4 ± 11.1 years old) were submitted to 24-hour ABPM and 5-day HBPM (triplicate morning and evening measurements). All underwent a standardized protocol for assessment of cardiovascular risk, sociodemographic and anthropometric data, laboratory evaluation (metabolic profile and renal function), transthoracic Doppler echocardiography and measurement of pulse wave velocity (PWV). The prevalence of refractory hypertension diagnosed by office BP, HBPM and ABPM were calculated. Sensitivity, specificity, predictive values, and likelihood ratios for HBPM were also calculated. Agreement between the procedures was evaluated using kappa coefficients and the Bland–Altman method. Results: The prevalence of refractory hypertension was 20.3% by ABPM and 18.9% by HBPM. Compared to resistant ones, refractory hypertensives diagnosed by HBPM are younger, with a higher prevalence of heart failure and higher levels of albuminuria. In turn, patients with RefHT diagnosed by ABPM are also younger, but they have a higher prevalence of stroke and previous cardiovascular disease, in addition to higher albuminuria. HBPM overestimated systolic BP by 11.2 ± 18.4 mmHg (correlation coefficient = 0.63; Bland-Altman coefficient = 37) and diastolic BP by 2.4 ± 9.2 mm Hg (correlation coefficient = 0.80; Bland-Altman coefficient = 18). The specificity, sensitivity, and positive and negative predictive values of HBPM in detecting RefHT diagnosed by ABPM were 88%, 98%, 97%, and 94%. The kappa coefficient showing excellent agreement (kappa = 0.884). Conclusions: HBPM presented good agreement with ABPM and can be used as a diagnostic method of refractory hypertension.