Repeated measures of FEV1 over 6 to 12 months: what change is abnormal?
Am J Respir Crit Care Med 2003 Apr; 167(7):A839
Longitudinal change in FEV1 (deltaFEV1) is useful for assessing adverse respiratory effects, but high variability impedes reliable recognition of accelerated decline in an individual. ATS (1991) recommends that a > 15% decline in FEV1 from year-to-year be the criterion for clinically significant abnormality. We examined the mean, lower 5th percentile, and lower 5% cutoff value (mean minus 1.64*SD) of deltaFEV1 in both percentage (%) and milliliter (ML) for 6- and 12-mo. intervals from actual data obtained using ATS recommended equipment and procedures in 389 white male coal miners and working nonminers (initial age 39, range 19-65 yrs) with 3 to 11 spirometry tests over 5 years. deltaFEV1 was 'normal' by the ATS criterion in 99.4% of tests separated by 12 mo. Results are shown for ALL participants, those with stable FEV1 (5 year slope < -90ml/ yr by linear regression)(STB), and nonsmokers without airway hyperresponsiveness who had no new symptoms over 5 years (NS0). The STB and NS0 results suggest that one year declines of greater than 8% or 330ml are unlikely when healthy working males perform spirometry according to ATS standards. These results have potential implication for interpretation of longitudinal FEV1 decline in individuals, and suggest that the 15% ATS criterion may be too large.
Respiratory-system-disorders; Coal-miners; Mine-workers; Spirometry; Smoking; Airway-obstruction; Airway-resistance; Surveillance
Disease and Injury: Asthma and Chronic Obstructive Pulmonary Disease
American Journal of Respiratory and Critical Care Medicine, 2003 International Conference, The American Thoracic Society, Seattle, WA, May 16-21, 2003