Figure 3. Comparison of the proportion of the fall in FEV₁ during methacholine challenge that is due to airway closure prior to and 12 months following bariatric surgery in obese asthmatic subjects.

Obese asthmatic subjects were grouped into those with elevated IgE (T_H2-high) and those with normal IgE (T_H2-low). The Closing Index, calculated as the % fall in FVC/% fall in FEV₁ at the highest dose of the methacholine challenge, was compared prior to and 12 month following bariatric surgery in obese asthmatic subjects. A larger closing index represents a greater proportion of overall bronchoconstriction attributed to airway closure.

The p-value shown is for the T_H2-status × surgery interaction factor

p = 0.03 for effect of surgery