Should FEV1/FEV6 replace FEV1/FVC ratio to detect airway obstruction? A metaanalysis

BACKGROUND

The conventional FEV(1)/FVC test is the "gold standard" to quantitate airway obstruction, but elderly subjects or patients with severe respiratory diseases quite frequently cannot make such an effort. Many studies have investigated the usefulness of FEV(1)/forced expired volume in 6 s (FEV(6)) measurements as an alternative for FEV(1)/FVC for diagnosis of airway obstruction. We conducted a meta-analysis to determine the FEV(1)/FEV(6) substitute for FEV(1)/FVC in the diagnosis of airway obstruction.

METHODS

After a systematic review of all-language studies, sensitivity, specificity, and other measures of accuracy of FEV(1)/FEV(6) in the diagnosis of airway obstruction were pooled using random-effects models. Summary receiver operating characteristic curves were used to summarize overall test performance.

RESULTS

Eleven studies met our inclusion criteria. The summary estimates for FEV(1)/FEV(6) in the diagnosis of airway obstruction in the studies included were as follows: sensitivity, 0.89 (95% confidence interval [CI], 0.83 to 0.93); specificity, 0.98 (95% CI, 0.95 to 0.99); positive likelihood ratio, 45.46 (95% CI, 18.26 to 113.21); negative likelihood ratio, 0.11 (95% CI, 0.08 to 0.17); diagnostic odds ratio, 396.02 (95% CI, 167.32 to 937.31); and diagnostic score, 5.98 (95% CI, 5.12 to 6.84).

CONCLUSIONS

FEV(1)/FEV(6) is a sensitive and specific test for the diagnosis of airway obstruction. FEV(1)/FEV(6) can be used as a valid alternative for FEV(1)/FVC in the diagnosis of airway obstruction.