PRTN3 and rheumatoid arthritis: We calculated the propensity scores from a logistic regression model with the following variables: age, gender, body mass index (BMI), duration of RA, history of smoking and drinking alcohol, current medication of NSAIDs, GCs, PPI or P-CAB, the positivity of RF and ACPA, and then, we matched these scores one by one using nearest-neighbor methods without replacement, and no caliper width.