R efractory hypertension (RH) is emerging as a significant and growing problem in managing hypertension. In a previous study (1), 11% of patients referred for uncontrolled hypertension were found to meet the criteria for RH. Not surprisingly, RH is associated with an increased risk of hypertensive target organ damage (2). Experts recommend 24 h ambulatory blood pressure monitoring (ABPM) to differentiate true RH from white-coat resistant hypertension (3). The test also provides information on nocturnal blood pressure (BP) and the means to assess its relationship with survival and the occurrence of cardiovascular and renal events, adjusted for daytime or 24 h BP (4-12). Several sleep BP pattern disturbances in normotensive (NT) and hypertensive subjects have been identified. A Japanese study (6) found a 20% increase in cardiovascular mortality for every 5% attenuation in nocturnal BP fall, independent of overall 24 h BP. In another study (13), a J-shaped curve of stroke incidence was found among extreme dippers (subjects with a 20% or greater fall in nocturnal BP) and nondippers, albeit from different causes, with risers (subjects with a paradoxical increase in nocturnal BP) having the worst cardiovascular prognosis. Recently, nighttime BP, independent of daytime level, was found to be a predictor of death and cardiovascular disease (12). Surprisingly, to date, little attention has been given to sleep BP patterns in subjects with RH, and the results in the existing literature conflict, at least in part, with the use of different definitions of the condition itself and methods to define the nighttime period (14-17).The present study was undertaken to determine whether sleep BP pattern disturbances are related to the presence or severity of hypertension. We used a widely accepted definition of RH and diaries BACKGROUND: Nocturnal blood pressure abnormalities are independently associated with an increased risk of death and cardiovascular disease. It is unclear, however, whether they are related to the presence or severity of hypertension. OBJECTIVES: To determine and compare the prevalence of sleep pattern disturbances in normotensive (NT) and hypertensive patients.
METHODS:The present cross-sectional study assessed the nocturnal blood pressure profiles from 24 h ambulatory blood pressure monitoring of refractory hypertensive (RH) (n=26), controlled hypertensive (CH) (n=52) and NT (n=52) subjects who were matched for age, sex and body mass index. Results are expressed as mean ± SD or proportion, as appropriate. RESULTS: During sleep, the percentage fall in mean arterial pressure was 15.1±6.1% in the NT group, 11.5±7.0% in the CH group and 7.7±7.7% in the RH group (P<0.0001). The corresponding proportions of nondipping were 25.0%, 42.3% and 61.5%, respectively (P=0.006), and those of nocturnal hypertension were 9.6%, 23.1% and 84.6%, respectively (P<0.0001). All pairwise comparisons of nocturnal blood pressure fall were significant. The proportion of subjects in the RH group who experienced a rise in nocturnal blood ...