Overlap syndrome "asthma and obstructive sleep apnea" in obese patients

Background: Asthma and obstructive sleep apnea (OSA) share not only poor sleep but also several risk factors and co morbidities such as obesity. The overlap syndrome “asthma and OSA” may have special characteristics in obese patients. The Aim: of this study was to describe the prevalence and the characteristics of the overlap syndrome “asthma and OSA” in obese patients. Method: A cross sectional study including 36 obese asthmatics was carried out during four months. Level of asthma control was assessed using asthma control test (ACT). Epworth sleepiness scale (ESS), STOP-Bang questionnaire (SBQ) and Berlin questionnaire (BQ) were used for OSA screening. Overnight respiratory polygraphy was done for all patients. Results: Obesity was severe in 43% of cases. OSA was confirmed in 83.3% of patients. The mean age of patients with overlap syndrome was 56.2±11 years and 66.6% of patients were female. ESS was > 8 in 48.6% of cases. BQ score was positive in 86% of cases and SBQ in 67% of cases. Mean AHI was 26.1/h. OSA was mild in 43.4% of cases, moderate in 26.6% of cases and severe in 30% of cases. According to ACT, asthma was uncontrolled in 46.4% of patients. A weak and negative correlation was found between AHI and ACT score (r=-0.21). Spirometry was normal in 23.8% of cases. Small airways involvement was observed in 42.8% of patients and 19% of patients had restrictive ventilator disorder. The therapeutic approach in 30% of these patients was home ventilation therapy. Conclusion: OSA is common in obese asthmatics. Poor control of asthma was frequent in patient with overlap syndrome OSA-asthma. Therefore, screening of OSA is important in obese and uncontrolled asthmatics.