Novel measure of lung function for assessing disease activity in asthma.

Introduction In asthma, lung function measures are often discordant with clinical features such as disease activity or control. Methods We investigated a novel technique that provides a measure (σCL) of unevenness (inhomogeneity) in lung inflation/deflation. In particular, we compared σCL with FEV1% predicted (FEV1%pred) as measures of disease activity in the asthmatic lung. Results σCL correlated modestly with FEV1%pred. However, σCL is not simply a proxy for FEV1%pred as the effects of salbutamol on the two parameters were unrelated. Importantly, σCL reflected disease control better than FEV1. Discussion We conclude that σCL shows promise as an objective measure of disease activity in asthma.