Obstructive sleep apnea-hypopnea (OSAH) is a risk factor for development of systemic arterial hypertension (SAH) and can worse the control of established SAH. We investigated the effects of long-term continuous positive airway pressure (CPAP) treatment in controlling and preventing SAH in a large cohort of subjects referred for sleep study for suspected OSAH.

In 495 subjects of whom 422 with OSAH and 73 without OSAH, the clinical history was obtained, arterial blood pressure was measured and the current anti-hypertensive drugs was recorded at diagnosis and/or at CPAP start. Subjects were interviewed after a follow-up period of (mean ± SD) 3.4 ± 2.2 yr (range 1–8 yr) and divided in patients with moderate-to-severe OSAH (n = 125) who referred to use CPAP regularly for at least 4 h every night (group 1), with moderate-to-severe OSAH (n = 70) who refused or abandoned the CPAP treatment after few weeks (group 2), with mild OSAH (n = 227) with no CPAP indication (group 3) and simple snorers or normals (n = 73) (group 4). For each group clinical status, BMI, and changes in SAH therapy and occurrence of SAH were assessed at the follow-up.

At the follow-up, a higher risk of increasing treatment for SAH was found for group 2 and group 3 versus group 1 (OR = 5, 95%CI 1–20, p < 0.01 and OR = 3, 95%CI 1–10, p < 0.05), respectively. The occurrence of SAH was lower (p < 0.001) in the group 1 (1.9%), vs group 2 (35.9%), 3 (21.1%) and 4 (18.6%).

In moderate-to-severe OSAH patients, long-term CPAP treatment significantly reduces the development of SAH and, in those with SAH at baseline, the need of anti-hypertensive drugs.