CPAP treatment has been inconsistently reported to improve airway responsiveness in asthmatic subjects.The purpose of our research was to determine the effects of nasal CPAP treatment on airway responsiveness and asthma quality of life in asthmatic subjects with obstructive sleep apnea syndrom (OSA).
Subjects with stable mild-moderate asthma were recruited following a diagnosis of OSA by polysomnography. They underwent 3 serial methacholine challenge tests and completed baseline specific OSA(QOLAp)and asthma(QOLAs) quality of life questionnaires; then laboratory nasal CPAP titration was performed and CPAP treatment was started. Following 6 weeks of treatment, the questionnaires and 3 serial methacholine challenge tests were repeated, as well as a controlled polysomnography on CPAP. No change in maintenance anti-asthmatic medication was allowed.
Twenty 49.2 ± 8.9 year old subjects (7F,13M) completed the study. Following 6 weeks of nocturnal CPAP used on the average of 7 hours ± 1, at a pressure of 9 cm H20 ± 3, the apnea-hypopnea index significantly dropped from 48 ± 24 to 3 ± 2 (p<0.001). No significant change in FEV1 (80.3 ± 13.6% pred) or PC20 (2.5 ± 1.8 mg/ml) occurred after CPAP treatment compared with baseline (82.2 ± 13.6% pred, 2.2 ± 1.4 mg/ml respectively). QOLAp significantly improved from 4,1 ± 1,4 at baseline to 6,0 ± 1,0 at the end of the study ( p<0.001) . There was also a significant improvement in QOLAs from 5,0 ± 1,2 at baseline to 5,8 ± 0,9 at the end of the study (p=0.001). QOLAs at baseline was inversely correlated with the BMI of the patient (rho=-0.5, p=0.01) and the improvement in QOLAs after CPAP treatment was positively correlated with the BMI (rho=0.5, p=0.03). There was no correlation between the improvement of QOLAp and QOLAs.
Although CPAP treatment does not alter airway responsiveness, it improves asthma quality of life in OSA and asthmatic patients.
Impact of CPAP treatment on the control of asthma in OSA and asthmatic patients should be assessed on the long term.
Chantal Lafond, None.