title: Effect of CPAP on blood pressure in patients with obstructive sleep apnea and resistant hypertension: the HIPARCO randomized clinical trial.
abstract: OBJECTIVE
  More than 70% of patients with resistant hypertension have obstructive sleep apnea (OSA). However, there is little evidence about the effect of continuous positive airway pressure (CPAP) treatment on blood pressure in patients with resistant hypertension.
  
  
  OBJECTIVE
  To assess the effect of CPAP treatment on blood pressure values and nocturnal blood pressure patterns in patients with resistant hypertension and OSA.
  
  
  METHODS
  Open-label, randomized, multicenter clinical trial of parallel groups with blinded end point design conducted in 24 teaching hospitals in Spain involving 194 patients with resistant hypertension and an apnea-hypopnea index (AHI) of 15 or higher. Data were collected from June 2009 to October 2011.
  
  
  METHODS
  CPAP or no therapy while maintaining usual blood pressure control medication.
  
  
  METHODS
  The primary end point was the change in 24-hour mean blood pressure after 12 weeks. Secondary end points included changes in other blood pressure values and changes in nocturnal blood pressure patterns. Both intention-to-treat (ITT) and per-protocol analyses were performed.
  
  
  RESULTS
  A total of 194 patients were randomly assigned to receive CPAP (n = 98) or no CPAP (control; n = 96). The mean AHI was 40.4 (SD, 18.9) and an average of 3.8 antihypertensive drugs were taken per patient. Baseline 24-hour mean blood pressure was 103.4 mm Hg; systolic blood pressure (SBP), 144.2 mm Hg; and diastolic blood pressure (DBP), 83 mm Hg. At baseline, 25.8% of patients displayed a dipper pattern (a decrease of at least 10% in the average nighttime blood pressure compared with the average daytime blood pressure). The percentage of patients using CPAP for 4 or more hours per day was 72.4%. When the changes in blood pressure over the study period were compared between groups by ITT, the CPAP group achieved a greater decrease in 24-hour mean blood pressure (3.1 mm Hg [95% CI, 0.6 to 5.6]; P = .02) and 24-hour DBP (3.2 mm Hg [95% CI, 1.0 to 5.4]; P = .005), but not in 24-hour SBP (3.1 mm Hg [95% CI, -0.6 to 6.7]; P = .10) compared with the control group. Moreover, the percentage of patients displaying a nocturnal blood pressure dipper pattern at the 12-week follow-up was greater in the CPAP group than in the control group (35.9% vs 21.6%; adjusted odds ratio [OR], 2.4 [95% CI, 1.2 to 5.1]; P = .02). There was a significant positive correlation between hours of CPAP use and the decrease in 24-hour mean blood pressure (r = 0.29, P = .006), SBP (r = 0.25; P = .02), and DBP (r = 0.30, P = .005).
  
  
  CONCLUSIONS
  Among patients with OSA and resistant hypertension, CPAP treatment for 12 weeks compared with control resulted in a decrease in 24-hour mean and diastolic blood pressure and an improvement in the nocturnal blood pressure pattern. Further research is warranted to assess longer-term health outcomes.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT00616265.
authors: Respiratory Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain.
authors: Miguel-Angel
authors: MA
authors: Martínez-García
authors: Francisco
authors: F
authors: Capote
authors: Francisco
authors: F
authors: Campos-Rodríguez
authors: Patricia
authors: P
authors: Lloberes
authors: María Josefa
authors: MJ
authors: Díaz de Atauri
authors: María
authors: M
authors: Somoza
authors: Juan F
authors: JF
authors: Masa
authors: Mónica
authors: M
authors: González
authors: Lirios
authors: L
authors: Sacristán
authors: Ferrán
authors: F
authors: Barbé
authors: Joaquín
authors: J
authors: Durán-Cantolla
authors: Felipe
authors: F
authors: Aizpuru
authors: Eva
authors: E
authors: Mañas
authors: Bienvenido
authors: B
authors: Barreiro
authors: Mar
authors: M
authors: Mosteiro
authors: Juan J
authors: JJ
authors: Cebrián
authors: Mónica
authors: M
authors: de la Peña
authors: Francisco
authors: F
authors: García-Río
authors: Andrés
authors: A
authors: Maimó
authors: Jordi
authors: J
authors: Zapater
authors: Concepción
authors: C
authors: Hernández
authors: Nuria
authors: N
authors: Grau SanMarti
authors: Josep María
authors: JM
authors: Montserrat
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents; D001794:Blood Pressure; D002940:Circadian Rhythm; D045422:Continuous Positive Airway Pressure; D004351:Drug Resistance; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D000959:Antihypertensive Agents