WASHINGTON – The risk of infection following orthopedic surgery is increased in patients with inflammatory rheumatic disease, compared with those with degenerative disease or traumatic injury, according to findings from a review of more than 50,000 surgical procedures.
The risk is greatest in those inflammatory rheumatic disease patients treated with conventional disease-modifying anti-rheumatic drugs (cDMARDs) or tumor necrosis factor (TNF) inhibitors, especially those receiving more than one cDMARD or TNF inhibitor with a long administration interval, and when surgery takes place without discontinuation of treatment, Catrina B. Scherrer reported at the annual meeting of the American College of Rheumatology.
Of 50,359 surgical procedures performed in 37,137 patients from a hospital surgery registry, 422 resulted in surgery-related infections. Of these infections, 49 occurred in 2,472 patients with an inflammatory rheumatic disease (IRD; 2%), and 373 occurred in 47,887 patients with degenerative disease/posttraumatic injury (0.8%). The difference was statistically significant, even after adjustment for other risk factors, including age, gender, diabetes, being overweight, cardiovascular disease, smoking, and type of surgery, said Ms. Scherrer of the Schulthess Clinic, Zürich.
The lowest rates of infection occurred with hand and shoulder surgery; the highest rates occurred with elbow surgery, she noted.
In 1,329 patients in the IRD group for whom complete information about medication was available, 171 (13%) had documented use of TNF inhibitors, and 49 of these (29%) discontinued treatment more than three administration intervals before surgery. Of the remaining 122 TNF inhibitor users, the time lag was three or fewer administration intervals.
An increased infection rate was seen in those who used more than one cDMARD (odds ratio, 2.425) and more than one TNF inhibitor (OR, 2.627) prior to surgery, and the risk of infection was increased tenfold when surgery was performed within one administration interval (OR, 10.047).
Patients who had their last treatment within one administration interval before surgery included 81% of infliximab users, compared with only 33% of adalimumab users and 24% of etanercept users, Ms. Scherrer noted.
Surgery patients in this study were followed over 8 years as part of a single-center surgery registry. The findings, which are limited by the study’s retrospective design and thus require confirmation in prospective studies, are nonetheless important because patients with aggressive disease such as IRDs frequently require orthopedic surgery.
The study findings suggest that IRD patients are, in general, at high risk of postoperative infection, that special attention should be paid to patients using more than one cDMARD or TNF inhibitor with long administration intervals, and that the last intake of TNF inhibitors – particularly infliximab – should be at least more than one administration interval before planned surgery, as the risk of postoperative infection is significantly increased if surgery occurs within this period, she concluded.
Ms. Scherrer reported having no disclosures.