To the Editor:
In a recent issue of The Journal, Khurana, et al1 report on the increased risk of lung cancer in patients with rheumatoid arthritis (RA) using administrative data from the Veterans Integrated Service Networks (VISN). The methodology and conclusions of the study raise several issues. The first is the definition of the diagnoses of RA and lung cancer used in the study. The authors state that the diagnosis of RA was based on International Classification of Diseases (ICD-9) coding of 714.0 in the computerized records without any other qualifying criteria. Published data show that an ICD-9 code for RA when combined with the receipt of a disease-modifying agent (DMARD) in the Veterans Affairs (VA) administrative databases has a sensitivity of 76%–88% and a specificity of 83%–97%2. Thus, use …
Address reprint requests to Dr. P. Ranganathan, Division of Rheumatology, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8045, St. Louis, MO 63110. E-mail: prangana{at}im.wustl.edu