To investigate the occurrence of lung cancer in patients with rheumatoid arthritis (RA) in the US veteran population. Patients with rheumatic diseases appear to have an increased risk for the development of lymphoproliferative and some solid organ malignancies.
We conducted a retrospective case control study using prospectively collected data from the Veterans Integrated Service Networks (VISN) 16 Veteran Affairs (VA) database from 1998 to 2004. We studied the association of RA and lung cancer and analyzed data on 483,721 VA patients. Patients were identified by searching for the diagnoses of RA and lung cancer based on the International Classification of Diseases (ICD) codes. We identified 8768 (1.81%) patients with a diagnosis of RA (ICD code 714.0), 7280 (1.5%) patients with lung cancer (ICD code 162.0), 247 patients with lung cancer and RA, and 7033 patients with lung cancer but no RA. Logistic regression analysis was performed to adjust for age, gender, race, and tobacco and asbestos exposure. Statistical tests were conducted at a 5% level of significance.
The diagnosis of RA was determined to have a significant association with lung cancer in this veteran population. Patients with RA are 43% (odds ratio 1.43) more likely to develop lung cancer than patients without RA, when adjusted for covariates.
Our study shows a significant positive association between RA and the development of lung cancer in the veteran population. Veterans with RA have an increased incidence of lung cancer when compared to the non-RA population.