Prognostic Value of Obstructive Sleep Apnea And Role of CPAP Treatment in the Incidence of Hypertensive Crisis.

Study Objectives: Hypertensive crises (HC) are not usually included in studies on the relationship between obstructive sleep apnea (OSA) and cardiovascular diseases. Consequently, our objective is to analyze the relationship between untreated OSA, treatment with CPAP and the incidence of HC.

Methods: Prospective study of 1,021 individuals recruited for clinical suspicion of OSA. Sleep parameters, medical history and HC were recorded during follow-up. HC was considered by the presence of SBP/DBP > 180/110 mmHg respectively in patients with compatible symptoms or damage of a target organ. Subjects were divided into three groups: (a) AHI ≤ 15;n = 401 (control group), (b) OSA treated with CPAP with good adherence; n = 362, and (c) AHI > 15 events/h with initial refusal of or non-compliance with CPAP treatment, n = 249.

Results: In the median follow up (16 [IQR: 13.7-17.8]) months, there were 58 incident HC events (7 the non-OSA group, 15 in the OSA group with good tolerance to CPAP, and 36 in the moderate-severe OSA group without/poor adherence to CPAP. Forty-six had arterial hypertension. In the survival analysis, those patients with moderate-to-severe OSA without CPAP had a fully adjusted risk of 2.91 (95%CI: 1.97-5.78; p < 0.001), with the CPAP-treated group showing no evidence of increased HC risk (HR 1.12; p:NS) compared to the control group. Among hypertensive subjects, the relationship between moderate-to-severe untreated OSA and the risk of HC was greatly enhanced: HR 7.22 (CI: 2.81-12.5; p < 0.001).

Conclusions: Untreated/non adherent to CPAP patients with moderate-to-severe OSA are at significantly higher risk of incident HC, particularly if they suffer from hypertension. Treatment with CPAP has a favorable effect by reduces the HC risk to control levels.