Continuous positive airway pressure for obstructive sleep apnoea does not improve asthma control

Background and objective Unrecognized obstructive sleep apnoea syndrome (OSAS) may lead to poor asthma control despite optimal therapy. We assessed asthma control, airway responsiveness, daytime sleepiness and health status at baseline and 3months after continuous positive airway pressure (CPAP) treatment among asthma patients with nocturnal symptoms and OSAS. MethodsResultsPatients with nocturnal asthma symptoms despite receiving at least moderate-dose inhaled corticosteroid and long-acting bronchodilators underwent a home sleep study using Embletta' portable diagnostic system. Patients with significant OSAS (apnoea-hypopnoea index (AHI) 10/h) were randomized to receive either CPAP or conservative treatment for 3months. Among 145 patients recruited, 122 underwent sleep study with 41 (33.6%) having AHI 10/h. Patients with significant OSAS had higher BMI (27.4 (5.1) vs 25.1 (4.5) kg/m(2), P =0.016), bigger neck circumference (36.6 (3.1) vs 34.8 (3.6) cm, P =0.006) and lower minimum SaO(2) (80.7 (6.6) vs 87.2 (3.9) %, P <0.001). Using intention-to-treat analysis among 37 patients with AHI 10/h (CPAP group (n =17) vs control group (n =20)), there was no significant difference in Asthma Control Test score (CPAP 3.2 (2.7) vs control 2.4 (5.7), P =0.568) but the CPAP group had a greater improvement in Epworth Sleepiness Scale (-3.0 (4.5) vs 0.5(3.8), P =0.014), Asthma Quality of Life Questionnaire (0.6 (0.8) vs 0.02 (0.7), P =0.022) and vitality domain in the SF-36 questionnaire (14.7 (16.8) vs 0.3 (16.2), P=0.012) after 3months. Data are presented as mean (SD) unless otherwise stated. ConclusionA high prevalence of OSAS was found among patients with asthma and snoring. CPAP therapy for 3months did not enhance asthma control but improved daytime sleepiness, quality of life and vitality. See In this randomized controlled trial involving patients with nocturnal asthma and snoring despite taking moderate-to-high-dose inhaled corticosteroid and long-acting bronchodilators, continuous positive airway pressure (CPAP) therapy for 3months did not improve asthma control but led to better asthma-related quality of life and vitality than those on conservative treatment.