Premium
Observer variation in classifying chest radiographs for small lung opacities and pleural abnormalities in a population sample
Author(s) -
Impivaara Olli,
Zitting Anders J.,
Kuusela Timo,
Alanen Erkki,
Karjalainen Antti
Publication year - 1998
Publication title -
american journal of industrial medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 104
eISSN - 1097-0274
pISSN - 0271-3586
DOI - 10.1002/(sici)1097-0274(199809)34:3<261::aid-ajim8>3.0.co;2-y
Subject(s) - medicine , radiography , kappa , cohen's kappa , population , radiology , lung , coefficient of variation , nuclear medicine , statistics , mathematics , environmental health , philosophy , linguistics
Background The purpose of this study was to assess inter‐ and intraobserver variation in the radiographic categories of small lung opacities (profusion) and pleural abnormalities classified according to the ILO classification of pneumoconioses with some modifications. Methods Chest radiographs derived from a representative adult population sample (n = 7,095) were classified by two radiologists. Observer variation was assessed on the basis of kappa (κ)‐type statistics. Results The observers agreed on profusion categories in 69% of cases of the total material. Up to 98% of the classifications fell into the same category or deviated by no more than one category. The corresponding kappa (κ) coefficient was 0.48 (95%CI = 0.46–0.49) and the weighted κ 0.72. When a selected subsample was reclassified by the observers, the proportions of crude agreement on profusion of small opacities ranged from 42% to 47% (weighted κ 0.52–0.55). The proportions of agreement on the main pleural abnormalities were 92% or over, and the corresponding κ coefficients at least 0.73. Conclusion The classification of lung opacities was subject to considerable observer variation, which calls for caution when results from different studies are compared. This variation, however, rarely exceeded one category, and thus appears to be small enough for meaningful comparisons between groups, at least within a single study. Am. J. Ind. Med. 34:261–265, 1998. © 1998 Wiley‐Liss, Inc.