Long-term gender-specific evolution of blood pressure under CPAP therapy in hypertensive patients with obstructive sleep apnea syndrome.

INTRODUCTION: Reduction of blood pressure (BP) under CPAP treatment in patients with obstructive sleep apnea syndrome (OSAS) associating hypertension (HT) is controversial and short-term evolution is often measured using the sphygmomanometer. PURPOSE: To study the variation in BP (sphygmomanometer and Holter) after 3 and 6 months of CPAP in OSAS patients associating hypertension. METHODS: We applied the exclusion criteria (hypoventilation, respiratory diseases, secondary hypertension, antihypertensive treatment modification during study, non-compliance) on 96 consecutive patients (SPSS 17.0: Chi test, T-test). RESULTS: 15 hypertensive patients (8.53 years from diagnosis) with OSAS succeeded six months of following: 3 women (20%), 12 men (80%) were comparable as age, body mass index and Epworth score; women had more severe OSAS. Sphygmomanometer measuring in men showed a decrease in systolic BP (SBP) (142 ± 8.9 to 128.7 ± 11.7 mmHg, p = 0.005) and diastolic BP (DBP) (82 ± 17.19 to 69.1 ± 6.6 mmHg, p = 0.040) at three months of treatment. Women had no changes at 3 and 6 months of assessment using the sphygmomanometer. BP Holter showed no significant changes in men; women exhibit a significant increase in maximum DBP/24 hours (104 ± 13.4 to 169.5 ± 27.5 mmHg, p = 0.034) and mean daytime DBP/24 hours (100 ± 14.1 to 166 ± 32.5 mmHg, p = 0.046) from 3 to 6 months. No group presents dipper status change to 3 or 6 months. CONCLUSIONS: The trend in both groups of increase in BP for 3 to 6 months is explained by the natural evolution of an old HT history. Long time monitoring using Holter device is more accurate in assessing cardiovascular risk.