OSA prevalence similar between resistant, refractory hypertension

The prevalence of obstructive sleep apnoea (OSA) is similar between resistant and refractory hypertensive patients, a study has shown. However, those with refractory hypertension are usually younger and have a better sleep pattern.

This cross-sectional study included 418 resistant hypertension patients (mean age 62.5 years, 30.9 percent male) who were submitted to a full-night polysomnography. Refractory hypertension referred to uncontrolled ambulatory blood pressure monitoring using five or more antihypertensive medications, including spironolactone.

The researchers performed bivariate analysis to compare resistant and refractory hypertension, as well as multivariate analysis to examine the independent correlates of OSA.

Ninety patients (21.5 percent) were diagnosed with refractory hypertension (mean age 58.5 years, 26.7 percent male). These patients, compared with resistant ones, were younger and had higher smoking and previous cardiovascular diseases prevalence, particularly stroke. Anthropometric measures did not differ.

Both groups had similar OSA prevalence (80.0 percent vs 82.9 percent) and moderate/severe OSA (51.1 percent vs 57.0 percent), as well as apnoea‒hypopnoea index. However, refractory patients had better sleep efficiency (78 percent vs 71 percent), with higher total sleep time (315 vs 281 min) and lower sleep latency (11 vs 17 min).

No between-group difference was noted in rapid eye movement sleep, oxygen saturation, microarousals index, and periodic limb movement.

“Refractory hypertension and OSA share common pathophysiological mechanisms and probably are intrinsically associated, but their prevalence, clinical profile, and polysomnography pattern remain misunderstood,” the researchers said.