Validation of FEV6 in the elderly: correlates of performance and repeatability

Background:Forced expiratory volume in 6 s (FEV6) has been proposed as a more easily measurable parameter than forced vital capacity (FVC) to diagnose airway disease using spirometry. A study was undertaken to estimate FEV6 repeatability, to identify correlates of a good quality FEV6 measurement and of volumetric differences between FEV6 and FVC in elderly patients.Methods:1531 subjects aged 65–100 years enrolled in the SA.R.A project (a cross-sectional multicentre non-interventional study) were examined. FEV6 was measured on volume-time curves that achieved satisfactory start-of-test and end-of-test criteria. Correlates of FEV6 achievement were assessed by logistic regression.Results:Valid FEV6 and FVC measurements were obtained in 82.9% and 56.9%, respectively, of spirometric tests with an acceptable start-of-test criterion. Female sex, older age, lower educational level, depression, cognitive impairment and lung restriction independently affected the achievement of FEV6 measurement. Good repeatability (difference between the best two values