Effect of CPAP on Blood Pressure in Patients With Obstructive Sleep Apnea and Resistant Hypertension: The HIPARCO Randomized Clinical Trial

• Autores: Miguel Ángel Martínez García, Francisco Capote Gil, Francisco Campos Rodríguez, Patricia LLoberes, M.J. Díaz de Atauri Rodríguez de los Ríos, María Somoza, Mónica González Blanco, Lirios Sacristán Bou, Ferrán Barbé Illa, Joaquín Durán Cantolla, Felipe Aizpuru Barandiaran, Eva Mañas, Bienvenido Barreiro, M. Mar Mosteiro Añón, Juan J. Cebrián, Mónica de la Peña Bravo, Francisco García Río, Andreu Maimó Bordoy, Jordi Zapater, Concepción Hernández, Nuria Grau, Josep Maria Montserrat
• Localización: JAMA: the journal of the American Medical Association, ISSN 0098-7484, Vol. 310, Nº. 22, 2013, págs. 2407-2415
• Idioma: inglés
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• Resumen

  • Importance 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.

    Design, Setting, and Participants 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.

    Interventions CPAP or no therapy while maintaining usual blood pressure control medication.

    Main Outcomes and Measures 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 and Relevance 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.

    Trial Registration clinicaltrials.gov Identifier: NCT00616265 Systemic hypertension is one of the most treatable cardiovascular risk factors.1 Between 12% and 27% of all hypertensive patients require at least 3 antihypertensive drugs for adequate blood pressure control and are considered patients with resistant hypertension.2- 4 Patients with resistant hypertension are almost 50% more likely to experience a cardiovascular event than hypertensive patients without resistant hypertension, and the incidence of resistant hypertension is expected to increase.5 Obstructive sleep apnea (OSA) affects 4% to 6% of the general middle-aged population6,7 and increases with age.8 It is characterized by the repeated collapse of the upper airway during the night, causing intermittent hypoxemia and sleep disruption, which in turn are associated with an increased risk for neurocognitive and cardiovascular morbidities.9 Recent studies have shown that OSA may contribute to poor control of blood pressure10 and that a very high percentage (>70%) of resistant hypertension patients have OSA.11 Accordingly, international guidelines now recognize OSA as one of the most common risk factors of resistant hypertension.4 Continuous positive airway pressure (CPAP) is the treatment of choice for severe or symptomatic OSA.12 A meta-analysis suggests that CPAP treatment reduces blood pressure levels to a clinically meaningful degree,13 but whether this positive effect is more pronounced in patients with resistant hypertension is unclear because studies on this issue are scarce and based on single-center approaches.14- 16 The objective of our study was to conduct a randomized, multicenter clinical trial to assess the effect of CPAP treatment on blood pressure values and nocturnal blood pressure patterns of patients with resistant hypertension and OSA.