A population-based case-control study on the association between rheumatoid arthritis and deep vein thrombosis

Objective: Chronic inflammation has been associated with endothelial dysfunction and altered coagulation status. However, at the present time, the data regarding the risk for developing deep vein thrombosis (DVT) in patients with rheumatoid arthritis (RA) is still scanty and conflicted. This study aimed to explore the frequency and association of DVT with RA using a population-based dataset. Methods: This was a case-control study conducted in Taiwan. A total of 5193 patients with DVT were identified from the Longitudinal Health Insurance Database 2000 (LHID2000) database. In total, 20,772 controls matched with cases in terms of gender, age, and year of index date were randomly selected. We used conditional logistic regression to calculate the odds ratio (OR) for having been previously diagnosed with RA between cases and controls. Results: Of the total 25,965 sampled subjects, 235 (0.9%) had been previously diagnosed with RA. Seventy-seven of these previous diagnoses were found among cases (1.5%) and 158 among controls (0.8%). Conditional logistic regression analysis revealed that cases were more likely to have had prior RA than controls (OR, 1.92; 95% confidence interval [CI], 1.46-2.53; P