When the changes in blood pressure over the study period were compared between groups by ITT , the CPAP group achieved a greater decrease in 24-hour mean blood pressure ( 3.1 mm Hg [ 95 % CI , 0.6 to 5.6 ] ; P = .02 ) and 24-hour DBP ( 3.2 mm Hg [ 95 % CI , 1.0 to 5.4 ] ; P = .005 ) , but not in 24-hour SBP ( 3.1 mm Hg [ 95 % CI , -0.6 to 6.7 ] ; P = .10 ) compared with the control group .