CPAP and hypertension in nonsleepy patients

Abstract

Question: Is continuous positive airway pressure (CPAP) therapy better than no therapy in reducing the incidence of hypertension or cardiovascular (CV) events in a cohort of nonsleepy patients with obstructive sleep apnea (OSA)?

Design: Randomized, controlled trial; no placebo CPAP used. ClinicalTrials.gov Identifier: NCT00127348.

Allocation: Randomization was performed using a computer generated list of random numbers in the coordinating center and results were mailed to participating centers in numbered opaque envelopes.

Blinding: Primary outcome was evaluated by individuals not involved in the study and who were blinded to patient allocation. Patients, investigators, and the statistician were not blinded.

Follow-up period: median 4 (interquartile range, 2.7-4.4) years.

Setting: 14 academic medical centers in Spain.

Subjects: 725 adults (mean age 51.8 y, 14% women) who were diagnosed with OSA with apnea hypopnea index (AHI) ≥ 20 events per hour and Epworth sleepiness score (ESS) ≤ 10 were randomized. Subjects with previous CV events were excluded. However, patients with a history of hypertension were not excluded (50% of the sample were hypertensive at baseline).

Intervention: Patients were randomized to receive CPAP treatment or no active intervention. All participants received dietary counseling and advice about sleep hygiene.

Outcomes: The primary outcome was the incidence of either systemic hypertension (among participants who were normotensive at baseline) or CV events (among all participants). The secondary outcome was the association between the incidence of hypertension or CV events (nonfatal myocardial infarction, nonfatal stroke, transient ischemic attack, hospitalization for unstable angina or arrhythmia, heart failure, and CV death) and the severity of OSA assessed by the AHI and oxygen saturation. The sample size was calculated assuming that the incidence of hypertension or new CV event in this population over a period of 3 years would be 10% annually; 345 patients per group were needed to detect a 60% reduction in incidence of new hypertension or CV events (90% power, 2-sided α = 0.05, assuming 10% study dropout).

Patient follow-up: 83% complete (only patients who received the allocated intervention were included in analysis of primary outcome).

Main results: A total of 147 patients with new hypertension and 59 cardiovascular events were identified (Table). In the CPAP group, there were 68 patients with incident hypertension and 28 CV events. Of the 357 participants in the CPAP group, 127 used CPAP < 4 hours/night (36%). In the control group, there were 79 patients with new hypertension and 31 CV events. There was no statistically significant difference between the groups in the primary outcome. TableRisk for incident hypertension or cardiovascular event

Conclusion: In adults with moderate to severe OSA and no symptoms of daytime sleepiness, CPAP therapy did not reduce incident hypertension or CV event compared with no active therapy.

Sources of funding: Instituto de Salud Carlos III (PI 04/0165) (Fondo de Investigaciones Sanitarios, Ministerio de Sanidad y Consumo, Spain), Spanish Respiratory Society (SEPAR) (Barcelona), Resmed (Bella Vista, Australia), Air Products-Carburos Metalicos (Barcelona), Respironics (Murrysville, Pennsylvania), and Breas Medical (Madrid, Spain).