Background Patients with rheumatoid arthritis (RA) are at an increased risk of malignancies compared with the general population.
Objectives The aim of this study was to evaluate the prevalence and risk factors of malignancy in National Health Insurance Service Ilsan hospital patients with seropositive RA.
Methods We found patients with seropositive RA who fulfilled the American College of Rheumatology criteria and American College of Rheumatology criteria/European League Against Rheumatism criteria, from May 2008 to September 2015. Occurrence of malignancy was originally collected by electronic medical record reports and diagnostic code. We consecutively enrolled patients with newly diagnosed malignancy. Control group was selected as five times the number of patients randomized.
Results Total 12 malignancies in 647 patients were newly identified during the retrospective observation period of 2051 person-years. Malignancy types were 3 lung cancers, 2 colon cancers, gastric cancer, breast cancer, thyroid cancer, cervix cancer, cholangiocarcinoma, lymphoma and parotid gland cancer. In multivariate logistic regression, the variables with independent predictive value were older age (age: odds ratio =1.11, 95% CI =1.01–1.22, p-value =0.02), rheumatoid factor (RF) negativity (RF positivity: odds ratio =0.06. 95% CI =0.01–1.27, p-value 0.07) In cox regression, the variables with independent predictive value were older age (age: hazard ratio =1.12, 95% CI =1.01–1.24, p-value =0.02), negative RF (RF positivity: hazard ratio =0.12. 95% CI =0.02–0.78, p-value 0.02), lower anti-cyclic citrullinated peptide (CCP) antibody titer (anti-CCP antibody titer: hazard ratio =0.98. 95% CI =0.96–0.99, p-value 0.03) and positive antinuclear-antibody (ANA) (ANA positivity: hazard ratio =14.97, 95% CI =0.87–255.05, p-value 0.06).
Conclusions Age, RF positivity, anti-CCP antibody titer, ANA positivity may be associated with malignancy risk in seropositive rheumatoid arthritis. So, continued vigilance and regular cancer screening are recommended for case of older age, RF negativity, lower anti-CCP antibody titer and ANA positivity.
Disclosure of Interest None declared