title: Assessment of reliability of lung function screening programs or longitudinal studies.
abstract: The aim was to determine reliability of lung function measurements performed according to recommendations of the American Thoracic Society (ATS) at a screening program in a large South African gold mine and to determine the usefulness of the reliability coefficient G for monitoring the reliability of lung function measurements in a mass screening program. The reliability coefficient G estimates the amount of random error of measurement, relative to the total variation in a measurement. The coefficient G was calculated as a correlation coefficient between two consecutive lung function tests performed within 6 mo, over a period of 43 mo on 3,378 miners. There was significant temporal variability in the reliability. For FEV(1), the coefficient G showed increased variability over the first 5 mo and stabilized at a value of 0.93 for the next 23 mo, after which it systematically declined over the next 15 mo. We estimated that in a large screening program, an optimal sample size of around 900 miners, examined randomly throughout the year, on a yearly basis, would provide a sufficient sample to examine monthly or quarterly fluctuation in the reliability. The value of the reliability coefficient G did not change when the time between two consecutive tests increased up to 15 mo. In conclusion, monitoring of lung function reliability in a screening program by the reliability coefficient G should improve data quality, and provide a measure on which the confidence in a decision-making process could be based when examining temporal changes in lung function for individual subjects.
authors.affiliation: National Center for Occupational Health, Johannesburg, South Africa. EXH6@cdc.gov
authors.forename: E
authors.initials: E
authors.lastname: Hnizdo
authors.forename: G
authors.initials: G
authors.lastname: Churchyard
authors.forename: D
authors.initials: D
authors.lastname: Barnes
authors.forename: R
authors.initials: R
authors.lastname: Dowdeswell
mesh_terms: D000328:Adult; D005541:Forced Expiratory Volume; D006046:Gold; D006801:Humans; D008137:Longitudinal Studies; D008173:Lung Diseases, Obstructive / Q000175:diagnosis; D008297:Male; D008403:Mass Screening; D008906:Mining; D009784:Occupational Diseases / Q000175:diagnosis; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D014797:Vital Capacity
chemical_list: D006046:Gold