Perioperative use of anti-rheumatic agents does not increase early postoperative infection risks: a Veteran Affairs' administrative database study

The aim of this study was to validate a novel technique that predicts stopping of disease-modifying anti-rheumatic drugs (DMARDs) and biologic agents (BA) from the Veterans Affairs (VA) database and compare infection risks of rheumatoid arthritis patients who stopped versus continued DMARDs/BA perioperatively. We identified 6,024 patients on 1 DMARD or BA in the perioperative period between 1999 and 2009. Time gap between medication stop date and the next start date predicted drug stoppage (X). Time gap between surgery date and stop date predicted whether stoppage was before surgery (Y). Chart review from Houston VA was used for validation. ROC analyses were performed on chart review data to obtain X and Y cutoffs. The primary endpoints were wound infections and other infections within 30 days. ROC analyses found X a parts per thousand yen 33 (AUC = 0.954) and Y a parts per thousand yen -11 (AUC = 0.846). Risk of postoperative infections was not different when stopping and continuing DMARDs/BA preoperatively. Stopping BA after surgery was associated with higher odds of postoperative wound (OR 14.15, 95 % CI 1.76-113.76) and general infection (OR 9.2, 95 % CI 1.99-42.60) compared to not stopping. Stopping DMARDs after surgery was associated with increased risk of postoperative general infection (OR 1.84, 95 % CI 1.07-3.16) compared with not stopping. There was positive association between stopping DMARDs after surgery and postoperative wound infection but failed to achieve statistical significance (OR 1.67, 95 % CI 0.96-2.91). There was no significant difference in postoperative infection risk when stopping or continuing DMARD/BA. Our new validated method can be utilized in the VA and other databases to predict drug stoppage.