Postsurgical Infection Risk Increased in Biologic-Treated RA

Arthroplasty of knee
Arthroplasty of knee
In Denmark, researchers found data that showed in patients with rheumatoid arthritis who undergo total hip and knee arthroplasty, infection is a risk factor and it is more pronounced in patients who are treated with biologics.

Rheumatoid arthritis (RA) diagnosis and treatment with biologic therapies has been linked to a higher risk for venous thromboembolism and infection following total knee or hip arthroplasty surgery, according to research published in Seminars in Arthritis and Rheumatism.

Researchers sought to examine the risk for medical complications following total knee and hip arthroplasty in patients with RA, specifically in patients treated with and without biologics, compared with patients with osteoarthritis (OA). Patients were part of a nationwide, register-based Danish cohort study between 2000 and 2014. Outcomes of interest included venous thromboembolism, myocardial infarction and stroke, and nonsurgical site infections. The cohort included 2899 patients with RA and 112,571 patients with OA who underwent total hip or knee surgery. At the time of surgery, patients in the RA cohort were younger and more likely to be women (66.1 vs 69.1 years; 73% vs 58%); patients were also more likely to have a total knee arthroplasty than a total hip arthroplasty surgery (63% vs 44%). In both groups, 99% of patients received thromboprophylaxis.  

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Patients in the RA group had a lower risk for deep vein thrombosis, pulmonary embolism, and venous thromboembolism; this decreased risk was driven by total knee arthroplasty. After excluding patients with either a history of venous thromboembolism, cancer, or both, hazard ratios (HRs) for venous thromboembolism were 0.81, 0.81, and 0.89, respectively (95% CI, 0.56-1.18; 95% CI, 0.56-1.17; and 95% CI, 0.61-1.29). Overall risk for postsurgical myocardial infarction or stroke was not increased in the RA group as a whole, but women within the RA group did have an increased risk estimate (HR 1.53; 95% CI, 0.91-2.56). When examining outcomes in biologic vs nonbiologic treated patients, patients who were treated with biologic therapies had a higher incidence and risk for venous thromboembolism compared with the nonbiologic group (1.9% vs 0.5%; HR 4.82; 95% CI, 1.67-13.90). Again, excluding patients with a history of venous thromboembolism, cancer, or both did not substantially change results. Patients in the biologic treatment group also had a higher rate of myocardial infarction or stroke (1% vs 0.6%). Researchers also observed an increased risk for infection in this group (HR 1.35; 95% CI, 0.65-2.80).

Limitations to the study include a lack of validation of start and stop date of biologic treatment as well as the risk for misclassification bias in the RA cohort subset.

“We found that following [total knee arthroplasty/total hip arthroplasty] surgery, RA was associated with increased risk of infections, mainly pneumonia, sepsis, and erysipelas, compared with OA,” the researchers concluded. “[T]he increased risk of postoperative [venous thromboembolism] among patients receiving biologics needs to be investigated further.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Cordtz R, Odgaard A, Kristensen LE, Overgaard S, Dreyer L. Risk of medical complications following total hip or knee arthroplasty in patients with rheumatoid arthritis: a register-based cohort study from Denmark [published online June 13, 2019]. Semin Arthritis Rheum. doi: 10.1016/j.semarthrit.2019.06.007