Effects of weight loss on asthma control in obese patients with severe asthma.

Studies on the effects of weight loss in patients with asthma are scarce. No studies have been performed in patients with severe asthma. Therefore, the aim of the present study was to assess the impact of weight loss in patients with severe asthma associated with obesity. This was an open, prospective, randomised study of two parallel groups, in patients with severe uncontrolled asthma and moderate obesity. The primary outcome was the level of asthma control 6 months after initiation of the weight reduction programme, quantified using the Asthma Control Questionnaire (ACQ). We evaluated clinical parameters, lung function, markers of airway inflammation and circulating cytokines. 22 patients were randomised to undergo treatment for obesity and 11 to the control group. The weight reduction programme was associated with significant improvements in asthma control (mean ± se ACQ score 3.02 ± 0.19 to 2.25 ± 0.28 in the treatment group versus 2.91 ± 0.25 to 2.90 ± 0.16 in the controls, p=0.001). This improvement was not accompanied by changes in markers of airway inflammation or bronchial reactivity, but by an increase in forced vital capacity. Our results suggest that weight reduction in obese patients with severe asthma improves asthma outcomes by mechanisms not related to airway inflammation.