title: Effect of continuous positive airway pressure on ambulatory BP in patients with sleep apnea and hypertension: a placebo-controlled trial.
abstract: BACKGROUND
  Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for arterial hypertension. Several controlled trials have investigated the effect of continuous positive airway pressure (CPAP) on BP in patients with OSAS, but its effect on hypertensive patients has not been analyzed specifically.
  
  
  OBJECTIVE
  To analyze the effect of CPAP on ambulatory BP in patients with OSAS and hypertension who were undergoing antihypertensive treatment.
  
  
  METHODS
  We conducted a parallel, randomized, placebo-controlled trial in 68 patients with OSAS and hypertension, who were receiving treatment with antihypertensive medication. Patients were randomly allocated to either therapeutic or subtherapeutic CPAP for 4 weeks. Ambulatory BP was registered at baseline and after treatment. Antihypertensive treatment was not changed during the study. Changes in BP were assessed on an intention-to-treat basis.
  
  
  RESULTS
  There were no baseline differences in the apnea-hypopnea index, comorbidities, or ambulatory BP between groups. Objective compliance with CPAP was similar in both the therapeutic and subtherapeutic groups (5.0 +/- 1.4 h/d vs 4.4 +/- 1.9 h/d, respectively; p = 0.13 [mean +/- SD]). There was a small and statistically nonsignificant decrease (- 0.3 +/- 6.3 mm Hg vs - 1.1 +/- 7.9 mm Hg; difference, - 0.8 mm Hg [95% confidence interval, - 2.7 to 4.3]; p = 0.65) in 24-h mean BP (24hMBP) in both subtherapeutic and therapeutic groups after 4 weeks of treatment. No significant changes in systolic, diastolic, daytime, or nighttime BP were observed. The normal circadian dipper pattern was restored in a higher proportion of patients in the therapeutic group compared to the subtherapeutic CPAP group, although differences were not significant (11 of 32 patients vs 3 of 25 patients; odds ratio, 3.84; 95% confidence interval, 0.82 to 20.30; p = 0.10). There was no correlation between the magnitude of change in 24hMBP and CPAP compliance, OSAS severity, or number of antihypertensive drugs used.
  
  
  CONCLUSIONS
  Four weeks of CPAP did not reduce BP in patients with OSAS and hypertension who were treated with antihypertensive medication, compared to placebo group.
authors.affiliation: Department of Respiratory Medicine, University Hospital, 41020 Sevilla, Spain. fcamposr@telefonica.net
authors.forename: Francisco
authors.initials: F
authors.lastname: Campos-Rodriguez
authors.forename: Antonio
authors.initials: A
authors.lastname: Grilo-Reina
authors.forename: Jose
authors.initials: J
authors.lastname: Perez-Ronchel
authors.forename: Mercedes
authors.initials: M
authors.lastname: Merino-Sanchez
authors.forename: Maria A
authors.initials: MA
authors.lastname: Gonzalez-Benitez
authors.forename: Manuel
authors.initials: M
authors.lastname: Beltran-Robles
authors.forename: Carmen
authors.initials: C
authors.lastname: Almeida-Gonzalez
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D018660:Blood Pressure Monitoring, Ambulatory; D045422:Continuous Positive Airway Pressure; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D000959:Antihypertensive Agents