title: Association between treated and untreated obstructive sleep apnea and risk of hypertension.
abstract: BACKGROUND
  Systemic hypertension is prevalent among patients with obstructive sleep apnea (OSA). Short-term studies indicate that continuous positive airway pressure (CPAP) therapy reduces blood pressure in patients with hypertension and OSA.
  
  
  OBJECTIVE
  To determine whether CPAP therapy is associated with a lower risk of incident hypertension.
  
  
  METHODS
  A prospective cohort study of 1889 participants without hypertension who were referred to a sleep center in Zaragoza, Spain, for nocturnal polysomnography between January 1, 1994, and December 31, 2000. Incident hypertension was documented at annual follow-up visits up to January 1, 2011. Multivariable models adjusted for confounding factors, including change in body mass index from baseline to censored time, were used to calculate hazard ratios (HRs) of incident hypertension in participants without OSA (controls), with untreated OSA, and in those treated with CPAP therapy according to national guidelines.
  
  
  METHODS
  Incidence of new-onset hypertension.
  
  
  RESULTS
  During 21,003 person-years of follow-up (median, 12.2 years), 705 cases (37.3%) of incident hypertension were observed. The crude incidence of hypertension per 100 person-years was 2.19 (95% CI, 1.71-2.67) in controls, 3.34 (95% CI, 2.85-3.82) in patients with OSA ineligible for CPAP therapy, 5.84 (95% CI, 4.82-6.86) in patients with OSA who declined CPAP therapy, 5.12 (95% CI, 3.76-6.47) in patients with OSA nonadherent to CPAP therapy, and 3.06 (95% CI, 2.70-3.41) in patients with OSA and treated with CPAP therapy. Compared with controls, the adjusted HRs for incident hypertension were greater among patients with OSA ineligible for CPAP therapy (1.33; 95% CI, 1.01-1.75), among those who declined CPAP therapy (1.96; 95% CI, 1.44-2.66), and among those nonadherent to CPAP therapy (1.78; 95% CI, 1.23-2.58), whereas the HR was lower in patients with OSA who were treated with CPAP therapy (0.71; 95% CI, 0.53-0.94).
  
  
  CONCLUSIONS
  Compared with participants without OSA, the presence of OSA was associated with increased adjusted risk of incident hypertension; however, treatment with CPAP therapy was associated with a lower risk of hypertension.
authors.affiliation: Respiratory Department, Hospital Universitario Miguel Servet, Zaragoza, Spain. jmmarint@unizar.es
authors.forename: José M
authors.initials: JM
authors.lastname: Marin
authors.forename: Alvar
authors.initials: A
authors.lastname: Agusti
authors.forename: Isabel
authors.initials: I
authors.lastname: Villar
authors.forename: Marta
authors.initials: M
authors.lastname: Forner
authors.forename: David
authors.initials: D
authors.lastname: Nieto
authors.forename: Santiago J
authors.initials: SJ
authors.lastname: Carrizo
authors.forename: Ferran
authors.initials: F
authors.lastname: Barbé
authors.forename: Eugenio
authors.initials: E
authors.lastname: Vicente
authors.forename: Ying
authors.initials: Y
authors.lastname: Wei
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Nieto
authors.forename: Sanja
authors.initials: S
authors.lastname: Jelic
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D020181:Sleep Apnea, Obstructive / Q000628:therapy*; D013030:Spain / Q000453:epidemiology