Effects of Obstructive Sleep Apnea and Gastroesophageal Reflux Disease on Asthma Control in Obesity

Background. Obesity is a risk factor for asthma. Obese asthmatics often have poor asthma control and respond poorly to therapy. It has been suggested that co-morbidities associated with obesity, such as reflux and obstructive sleep apnea, could be important factors contributing to poor asthma control in obese patients. Objectives. The purpose of this study was to determine if (1) reflux and/or (2) symptoms of sleep apnea contribute to poor asthma control in obesity. Methods. We studied asthmatic subjects participating in a trial of reflux treatment. Participants underwent baseline evaluation of asthma symptoms and lung function. Overall 304 participants underwent esophageal pH probe testing; 246 participants were evaluated for obstructive sleep apnea symptoms. Results. Of 402 participants in this trial, 51% were obese. Role of reflux in asthma control. Those with higher body mass index (BMI) reported a higher prevalence of reflux symptoms, but the prevalence of pH probe acid reflux was similar in all groups. Reflux was not associated with measures of asthma control in obese patients. Role of obstructive sleep apnea in asthma control. Symptoms and self-report of obstructive sleep apnea were more common with increasing BMI and associated with worse asthma control as measured by the Juniper Asthma Control questionnaire and Asthma Symptom Utility Index. Conclusions. Our data suggest that obstructive sleep apnea, but not gastroesophageal reflux disease, may contribute significantly to poor asthma control in obese patients.