Abstract: Objective To study the characteristics of blood pressure variability in the hypertensive patients with moderate or severe obstructive sleep apnea syndrom,which will help to reveal the causes of high morbidity of cardio-cerebral vasuclar events.Methods Ninety-four patients were divided into the control group(hypertension with mild obstructive sleep apnea,n=58,mean age(52±2.7)y, body mass index(27.3±0.98)kg/m² and OSAS group(hypertension with moderate or severe OSAS,mean age(46±1.6)y,body mass index(28.2±0.48)kg/m² according to the results of clinical blood pressure,24 h ambulatory blood pressure monitoring(ABP) and polysomnography(PSG).Results 1) The two groups are age,sex and body mass index matched.The rate of non-dipper profile in OSAS group(55.6%) is significantly higher than that of the control group(22.4%).2) Mean pulse pressure(PP) in 24 h,daytime and nighttime,in OSAS group((49.57±13.27)mmHg,(49.53±12.92)mmHg,(50.31±16.86)mmHg) is significantly higher than that of the control group((44.69±7.12)mmHg,(45.12±7.50)mmHg,(42.69±6.28)mmHg respectively)(P<0.05).Conclusion Moderate and severe OSAS affects the rhythm of blood pressure variability as well as does the pulse pressure.

Key words: hypertension, obstructive sleep apnea, blood pressure variability, pulse pressure