Should FEV1/FEV6 Replace FEV1/FVC Ratio To Detect Airway Obstruction? A Metaanalysis

Background: The conventional FEV1/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 FEV1/forced expired volume in 6 s (FEV6) measurements as an alternative for FEV1/FVC for diagnosis of airway obstruction. We conducted a metaanalysis to determine the FEV1/FEV6 substitute for FEV1/FVC in the diagnosis of airway obstruction. Methods: After a systematic review of all-language studies, sensitivity, specificity, and other measures of accuracy of FEV1/FEV6 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 FEV1/FEV6 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: FEV1/FEV6 is a sensitive and specific test for the diagnosis of airway obstruction. FEV1/FEV6 can be used as a valid alternative for FEV1/FVC in the diagnosis of airway obstruction.