title: Continuous positive airway pressure reduces blood pressure in patients with obstructive sleep apnea; a systematic review and meta-analysis with 1000 patients.
abstract: BACKGROUND
  Obstructive sleep apnea (OSA) may lead to the development of hypertension and therapy with continuous positive airway pressure (CPAP) can promote reduction in blood pressure.
  
  
  OBJECTIVE
  The objective of this study is to review systematically the effects of CPAP on blood pressure in patients with OSA.
  
  
  METHODS
  The search was conducted in the following databases, from their beginning until February 2013: MEDLINE, Embase, Cochrane CENTRAL, Lilacs and PEDro. In addition, a manual search was performed on references of published studies. Randomized clinical trials (RCTs) that used CPAP compared with placebo CPAP or subtherapeutic CPAP for treatment of patients with OSA and that evaluated office SBP and DBP and 24-h ambulatory blood pressure were selected.
  
  
  RESULTS
  Sixteen RCTs were included among 3409 publications, totaling 1166 patients. The use of CPAP resulted in reductions in office SBP [-3.20  mmHg; 95% confidence interval (CI) -4.67 to -1.72] and DBP (-2.87  mmHg; 95% CI -5.18 to -0.55); in night-time SBP (-4.92  mmHg; 95% CI -8.70 to -1.14); in mean 24-h blood pressure (-3.56  mmHg; 95% CI -6.79 to -0.33), mean night-time blood pressure (-2.56  mmHg; 95% CI -4.43 to -0.68) and 24-h DBP (-3.46  mmHg; 95% CI -6.75 to -0.17). However, no significant change was observed in daytime SBP (-0.74  mmHg; 95% CI -3.90 to 2.41) and daytime DBP (-1.86  mmHg; 95% CI -4.55 to 0.83).
  
  
  CONCLUSIONS
  Treatment with CPAP promoted significantly but small reductions in blood pressure in individuals with OSA. Further studies should be performed to evaluate the effects of long-term CPAP and the impact on cardiovascular risk.
authors: aInstituto de Cardiologia do Rio Grande do Sul/Fundação Universitária de Cardiologia bUniversidade Federal do Rio Grande do Sul cUniversidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil.
authors: Andressa S O
authors: AS
authors: Schein
authors: Alessandra C
authors: AC
authors: Kerkhoff
authors: Christian C
authors: CC
authors: Coronel
authors: Rodrigo D M
authors: RD
authors: Plentz
authors: Graciele
authors: G
authors: Sbruzzi
mesh_terms: D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D006801:Humans; D006973:Hypertension / Q000209:etiology / Q000628:therapy*; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000503:physiopathology