Changing rheumatoid arthritis medication stop time may help reduce flare-ups.

Researchers reviewed the charts of 194 total knee replacement patients (mean age 67.7 years; 86.6% female) identified as having rheumatoid arthritis through ICD-9 codes or self-report between June 2007 and May 2010, analyzing flare at 1 month postoperatively and adverse events at 6 months postoperatively, including surgical site infection, deep venous thrombosis, infection, reoperation, pneumonia and pulminary embolus, according to the abstract.

“We need to do more studies to see if more pharmacologically based timing of when you hold these medications — maybe tie it more to their half-life — might potentially decrease rates of postoperative flares,” Lisa Mandl, MD, MPH, lead author and rheumatologist at the Hospital for Special Surgery, stated in a press release.

The stop time observed for many of the anti-tumor necrosis factor (anti-TNF) medications are between 2 weeks to 4 weeks before surgery but did not correlate with the half-life of the drug. Etanercept (Enbrel, Pfizer) has a half-life of 3 days to 5.5 days but the average stop time recorded was 2.4 weeks preoperatively. The drug adalimumab (Humira, Abbott) was stopped at an average of 4.6 weeks before surgery but the half-life is only between 1.4 weeks to 2.9 weeks. Infliximab (Remicade, Janssen) was stopped at an average of 4.9 weeks when the half-life is between 1 to 1.7 weeks.

Despite the discrepency in stop times, there was no significant difference in adverse events in the anti-TNF group, according to the abstract.

“At least in this relatively small sample, it doesn’t look like there are any increases in infections or blood clots or other problems that go along with these anti-TNFs, which is comforting for patients who are on these drugs who are going in for surgery,” Mandl said.

Among the patients studied, there were two pulmonary embolus, one deep venous thrombosis, two surgical site infections and two reoperations. Four of the adverse events were in the anti-TNF group.

“Maybe we won’t have to stop patients so early,” Mandl said. “We need to think a bit more about how we hold them to optimize how patients do after surgery.”

Reference:

• Johnson B, Goodman SM, Alexiades M, Mandl LA. The influence of demographic factors, surgical approaches and implant design on long-term outcome of total hip replacement. Paper #2224. Presented at the 2011 American College of Rheumatology Annual Scientific Meeting. Nov 5-9. Chicago.

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