Validation and characterization of venous thromboembolism diagnoses in the Swedish National Patient Register among patients with rheumatoid arthritis.

This study demonstrates high validity for VTE diagnoses recorded in the NPR for patients with RA, thus confirming that the NPR may be used to identify prevalent VTE as well as incident VTE events in patients with RA. Our results further demonstrate that in patients with RA, diagnoses of VTE are only marginally influenced by work-up related to the rheumatic disease, suggesting a modest impact of surveillance or diagnostic bias.