title: Long-term effect of continuous positive airway pressure on BP in patients with hypertension and sleep apnea.
abstract: OBJECTIVE
  To analyze the long-term effect of continuous positive airway pressure (CPAP) on ambulatory BP in patients with obstructive sleep apnea (OSA) and hypertension, and to identify subgroups of patients for whom CPAP could be more effective.
  
  
  METHODS
  We conducted a prospective, long-term follow-up trial (24 months) in 55 patients with OSA and hypertension (mean CPAP use, 5.3 +/- 1.9 h/d [+/- SD]). Twenty-four-hour ambulatory BP monitoring (ABPM) was measured at baseline and after intervention with CPAP on an intention-to-treat basis. In addition, the correlation between the changes in 24-h mean arterial pressure (24hMAP) and CPAP compliance, OSA severity, and baseline ABPM was assessed.
  
  
  RESULTS
  At the end of follow-up, a significant decrease was shown only in diastolic BP (- 2.2 mm Hg; 95% confidence interval [CI], - 4.2 to - 0.1; p = 0.03) but not in 24hMAP or other ABPM parameters. However, a correlation between changes in 24hMAP and baseline systolic BP (r = - 0.43, p = 0.001), diastolic BP (r = - 0.38, p = 0.004), and hours of use of CPAP (r = - 0.30, p = 0.02) was observed. A significant decrease in the 24hMAP was achieved in a subgroup of patients with incompletely controlled hypertension at entry (- 4.4 mm Hg; 95% CI, - 7.9 to - 0.9 mm Hg; p = 0.01), as well as in those with CPAP compliance > 5.3 h/d (- 5.3 mm Hg; 95% CI, - 9.5 to - 1.2 mm Hg; p = 0.01). Linear regression analysis showed that baseline systolic BP and hours of CPAP were independent predictors of reductions in BP with CPAP.
  
  
  CONCLUSIONS
  Long-term CPAP reduced BP modestly in the whole sample. However, patients with higher BP at entry and good CPAP compliance achieved significant reductions in BP.
authors.affiliation: Departments of Respiratory Medicine, Valme University Hospital 41020 Sevilla, Spain. fcamposr@telefonica.net
authors.forename: Francisco
authors.initials: F
authors.lastname: Campos-Rodriguez
authors.forename: Jose
authors.initials: J
authors.lastname: Perez-Ronchel
authors.forename: Antonio
authors.initials: A
authors.lastname: Grilo-Reina
authors.forename: Jorge
authors.initials: J
authors.lastname: Lima-Alvarez
authors.forename: Maria A
authors.initials: MA
authors.lastname: Benitez
authors.forename: Carmen
authors.initials: C
authors.lastname: Almeida-Gonzalez
mesh_terms: D018660:Blood Pressure Monitoring, Ambulatory; D045422:Continuous Positive Airway Pressure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000503:physiopathology / Q000628:therapy*; D018709:Statistics, Nonparametric; D016896:Treatment Outcome