title: Nocturnal blood pressure profiles among normotensive, controlled hypertensive and refractory hypertensive subjects.
abstract: 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.
  
  
  OBJECTIVE
  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 pressure (19.2%) was significantly greater than the proportions in the NT and CH groups (P=0.001), as was the proportion of subjects with nocturnal hypertension (P<0.0001). There was less extreme dipping in RH, although the difference was not statistically significant (P=0.08).
  
  
  CONCLUSIONS
  A significantly higher prevalence of nondipping, nocturnal hypertension and nocturnal blood pressure rising in RH was demonstrated. These sleep disturbances or independently, their cause, may account for the difficulties in attaining blood pressure control.
authors.affiliation: Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada.
authors.forename: Oded
authors.initials: O
authors.lastname: Friedman
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Logan
mesh_terms: D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods; D002940:Circadian Rhythm / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D015995:Prevalence; D011379:Prognosis; D012720:Severity of Illness Index