NIV Congres

Background: Asthma in obese subjects is poorly understood and the effect of weight loss on asthma control is not well described.

Aim: To investigate the effects of bariatric surgery on asthma control, quality of life and lung function.

Methods: We performed a prospective study in patients with a confirmed diagnosis of asthma (FEV₁ ≥ 12% and/or PD20 < 1.76 mg (= bronchial hyperresponsiveness, BHR)) and non-asthmatic patients undergoing bariatric surgery (BMI > 35kg/m², age 18-50y). Lung function, medication and quality of life were assessed at baseline and 3 months after bariatric surgery. Obese asthmatics who did not undergo bariatric surgery served as an additional control group.

Results: 35 asthma patients (BS+A) and 50 non-asthmatics (BS-A) underwent bariatric surgery, 17 asthma patients served as controls (NBS+A). Only BMI of NBS+A (41 kg/m²) was significantly lower compared to BS+A (46 kg/m²) or BS-A (44 kg/m²), while there were no other differences between the groups at baseline (e.g. comorbidity, lung function). Following bariatric surgery, BMI decreased to 38 kg/m² in BS+A and 36 kg/m² in BS-A, and remained stable in NBS+A group (41 kg/m²). There were no differences in asthma control questionnaire (ACQ), asthma related quality of life questionnaire (AQLQ), FEV₁ or FeNO between the two asthma groups (BS+A and NBS+A) at baseline. Following surgery, ACQ and AQLQ significantly improved in BS+A group (1.4 to 0.7, p = 0.045; respectively 4.9 to 6.1, p = 0.002), whereas no change was detectable after 3 months in NBS+A (1.5 to 1.2, p = 0.275; respectively 5.3 to 5.2, p = 0.676). The group without asthma (BS-A) also showed a significant improvement in ACQ (0.6 to 0.1, p = 0.002) and AQLQ (5.0 to 6.7, p = 0.001) 3 months after bariatric surgery. There was no change in FeNO in any group. FEV₁ improved significantly only in BS+A (mean 86.2 to 92.4% predicted, p = 0.001). After surgery, a 50% reduction in BHR was observed in BS+A (88% to 46%).

Conclusion: Bariatric surgery improves lung function, asthma control and quality of life in patients with asthma and morbid obesity already after 3 months. This suggests that weight loss can be an important component of the management of obese asthmatics. Non-asthmatic obese controls also have asthma-like symptoms, which underlines the importance of adequate diagnosis of asthma in the morbidly obese.