Impulse oscillometry metrics differentiate adults with asthma from non-asthmatic controls: a meta-analysis

Abstract

Background

Impulse oscillometry (IOS), an effort-independent technique, assesses both central and peripheral airway function. The latter are major sites of inflammation in asthma, suggesting that IOS may help diagnose asthma. However, previous IOS studies, limited by sample size, report mixed results. Our objective was to establish whether IOS-based airway metrics can differentiate adults with asthma from non-asthmatic subjects.

Methods

A meta-analysis of 11 published oscillometric studies was performed including adult (18-70 years) patients with well-controlled asthma and non-asthmatic controls.  Sensitivity analysis was applied to assess the degree of heterogeneity. In addition, Minimal Clinical Important Difference (MCID) was determined.

Results           

There were no significant differences in general demographics between study populations, consisting of 410 asthma patients and 211 controls. Significant differences between study populations were observed for FEV1 % predicted and all IOS metrics, with highly significant SMD differences for R5 -0.88 (p<0.0001), R5-R20 -0.85 (p<0.0001), X5 -0.78 (p<0.0001), and AX -1.15 (p=0.0300). The MCID for R5 was 0.046 kPa/L/s, R5-R20 0.013 kPa/L/s, X5 -0.022 kPa/L/s, and AX 0.088 kPa/L.

Conclusion

IOS-determined airway resistance (R5, R5-R20) and reactance (X5 and AX) can differentiate individuals with (controlled).