Sapiña-Beltrán E, et al. - In 131 normotensive obstructive sleep apnoea (OSA) outpatients (with an apnoea/hypopnoea index [AHI] greater than 15 events/hour) receiving continuous positive airway pressure (CPAP) treatment, researchers assessed the blood pressure (BP) changes. At baseline and after 6 months, a sleep study and 24-h ambulatory BP monitoring (ABPM) were performed in all patients. The presence of baseline masked hypertension was also investigated. Mildly reduced all 24-h ABPM variables but statistically significantly attenuated mean 24-h DBP, mean daytime DBP and the mean 24-h ambulatory BP were observed after 6 months of CPAP treatment. The attenuation was mainly attributed to BP alterations in subjects with masked hypertension who exhibited a mean BP reduction of −4.78 mmHg. At 6 months, nondippers had a reduction in mean nocturnal BP of −4.73 mmHg, which was consistent with a circadian BP pattern, whereas, dippers showed an increase in mean nocturnal BP by 2.61 mmHg. Overall, ABPM evaluation is necessary for such patients.