When we assessed the spirometry measures FEV 1 and FVC in % predicted, as well as FEV 1 /FVC, we observed statistically significant differences with exacerbation severity, and between out-and in-patients ( Figures 1A-D and 2A -B). One draw-back was the paucity of such information in Level III studies. This confirms the clinical situation that as exacerbations worsen and more specialised care is required, spirometry measurements are less likely under baseline conditions or during an exacerbation [14] . Thus, such data is rare in many published studies.