Rheumatoid arthritis

Biologics compared for infection risk after arthroplasty for RA

Rates of serious postoperative infection and 30-day readmissions after total joint arthroplasty are similar in patients with rheumatoid arthritis (RA) regardless of their exposure to different biologic therapies.

However glucocorticoid use is associated with a greater risk of adverse outcomes, suggesting that minimising their use should be a bigger focus for perioperative management.

The retrospective cohort study included about 10,000 patients with RA who underwent either a total knee or hip arthroplasty including primary and revision procedures.

The US study found rates of 30-day readmission for infection, including urinary tract infections, skin and soft tissue infections, and pneumonia, ranged from 4.7% in one data set to 9.0% in Medicare data.

Rates were similar across biologic treatment groups.

Prosthetic joint infections (PJI) within one year occurred in 2.0% to 2.6% of procedures, with no significant difference in rates across most of the biologics.

Glucocorticoid exposure however was associated with a dose-dependent increase in risks for hospitalised infection, PJI, non–urinary tract hospitalised infection, and readmission in both data sets.

“Rates of PJI were numerically greater with glucocorticoids, 5 to 10 mg/d (HR, 1.36 [CI, 0.90 to 2.04]), and significantly greater with 10 mg/d (HR, 1.86 [1.02 to 3.37]),” the study said.

“Predicted 1-year cumulative incidence was 2.83% (CI, 1.88% to 4.21%) for 5 to 10 mg/d and 3.83% (CI, 2.13% to 6.87%) for more than 10 mg/d, compared with 2.09% without glucocorticoids.”

Concomitant use of methotrexate was not associated with greater risk for any of the outcomes.

The study authors said recent US guidelines recommend withholding bDMARDs for one dosing interval before joint replacement surgery and avoiding glucocorticoid doses above 20 mg/day.

“The results of this study suggest that postoperative risk may be increased even with lower dosages of glucocorticoids (5 to 10 mg/d),” the researchers said.

Dr Peter Lewis, deputy director of the Australian Orthopaedic Association National Joint Replacement Registry, told the limbic the rate of joint replacement for RA has dramatically reduced over the last 20 years.

This was mostly thought to be due to the use of biologics, he said.

A recent comparison of knee replacement outcomes in RA and osteoarthritis patients confirmed however that RA patients, particularly males, have a higher risk of revision due to infection.

“We don’t really understand why there is this difference. There may be some contribution from the disease, or medications for it, causing a level of immunocompromise,” he said.

An editorial in the Annals of Internal Medicine said the study unfortunately did not include a non-biologic treatment arm and could not discriminate between patients whose biologic may have been withheld.

“An obvious concern about withholding biologic therapies in the perioperative periods is that this may result in RA flare, necessitating an increase in glucocorticoid dosage,” the Canadian authors said.

The study did not stratify on primary or revision surgeries either.

The authors said the findings should be reassuring regarding the lack of evidence for increased infection risk with methotrexate–biologic cotherapy, which almost half of the study population was receiving.

“However, the study does not resolve the question of whether withholding biologic therapies in the perioperative period actually reduces patients’ overall risk for infection complications.”

“Although not addressed by the current study, surgeon and hospital experience performing joint replacement surgery in patients with RA should be considered in physician referral to optimize patient outcomes,” they added.

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