The Factors Affecting the Non-dipper Pattern in Japanese Patients with Severe Obstructive Sleep Apnea

OBJECTIVE: Obstructive sleep apnea (OSA) is assumed to influence the circadian blood pressure (BP) fluctuation, particularly causing nocturnal hypertension and changing the dipping pattern of nocturnal BP. This study aimed to clarify the triggers of the non-dipper pattern in nocturnal BP in Japanese patients with severe OSA (the apnea-hypopnea index ≥30/h). METHODS: Of 541 patients with OSA diagnosed using polysomnography (PSG) and ambulatory BP monitoring (ABPM), 163 patients <60 years of age (Younger group) and 101 patients ≥60 years of age (Older group) were stratified into the dipper or non-dipper pattern groups. RESULTS: A logistic regression analysis was performed using a non-dipper pattern as a dependent variable. A multivariate analysis demonstrated that the cumulative percentage of time at saturation below 90% was the only independent risk factor for the non-dipper and riser patterns in the Younger group (odds ratio, 1.022; 95% confidence interval, 1.001-1.044; p=0.035), whereas slow-wave sleep (odds ratio, 0.941; 95% confidence interval, 0.891-0.990; p=0.019) and the use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers (odds ratio, 2.589; 95% confidence interval, 1.051-6.848; p=0.039) were risk factors in the Older group. CONCLUSION: These findings suggested that the degree of desaturation in young OSA patients and sleep quality in old OSA patients might influence the dipping patterns in nocturnal BP.