High SBP Associated With Hypertensive Crisis in OSA-Induced Hypertension

A team of investigators evaluating patients with hypertension caused by obstructive sleep apnea (OSA) found that 15.7% experienced hypertensive crisis (HTC) and that hypertensive crisis was associated with elevated systolic blood pressure (SBP) in those patients, according to research published in BMC Cardiovascular Disorders.

From 2015 to 2016, the researchers conducted a retrospective study in Thailand of 121 adults aged 18 years and older with OSA-induced hypertension. The primary outcome was HTC, defined as systolic blood pressure higher than 180 mm Hg or diastolic blood pressure (DBP) higher than 110 mm Hg. Acute and nonacute organ damage as a result of HTC were defined as hypertensive emergency and hypertensive urgency, respectively.

The researchers found that 15.7% (n=19) of those studied experienced prior HTC (hypertensive urgency, n=15; hypertensive emergency, n=4). Elevated SBP and DBP differed significantly in patients with and without HTC. Patients with OSA-induced HTC had a median SBP of 177 mm Hg and DBP of 108 mm Hg, while those without HTC had a median SBP of 141 mm Hg and DBP of 85 mm Hg. Overall, among the numerous potential risk factors for HTC examined, only SBP was independently associated with hypertensive crisis (adjusted odds ratio, 1.046; 95% CI, 1.012-1.080).

According to the researchers, “these results may indicate that patients with hypertension caused by OSA are at higher risk for hypertensive crisis.” Study results indicated that SBP at baseline was a significant risk factor for HTC; factors such as age, snoring, and large circumference of the neck did not show a significant association with HTC.

Study limitations included the retrospective nature of the research and differing definitions for HTC diagnosis in other research. However, the study authors noted that HTC definition difference had minimal impact on enrollment in this study.

The researchers state that, “OSA cannot be assumed to be the cause of hypertensive crisis. However, our aim was to determine the risk factors for hypertensive crisis in these patients, not to show a causal relationship between OSA and hypertensive crisis.”

Reference

Khamsai S, Chootrakool A, Limpawattana P, et al. Hypertensive crisis in patients with obstructive sleep apnea-induced hypertension. BMC Cardiovasc Disord. 2021;21(1):310. doi:10.1186/s12872-021-02119-x