While pursuing a doctorate in physics, Kaleb Michaud made a hairpin turn in his career path and chose instead to apply his expertise in statistics to rheumatic diseases. Michaud’s decision, boosted with some funding from the Arthritis Foundation, is already making a difference in patients’ lives, not only current patients but future patients as well.

Now an assistant professor at the University of Nebraska, Michaud received a New Investigator grant from the Arthritis Foundation in 2008 to study the impact of total joint replacement in people with rheumatoid arthritis (RA). Even though one out of four people with RA will likely have total joint replacement (TJR), most research on the effects of TJR has been in osteoarthritis (OA) and not RA. 

For starters, RA and OA are different diseases. People with RA face a higher risk of infection and cardiovascular problems, which are also two of the complications of TJR surgery. Doctors may worry that replacing damaged joints with their engineered counterparts in RA patients will cost more and worsen recovery.

Answers in Medical Databases

Studying joint replacement in people with RA will help patients understand how well the procedure works and what results patients can expect, such as how much swelling and pain will remain after surgery, how they’ll feel and whether cardiovascular problems or risk of infection will complicate the surgery.

To answer such questions, Michaud and colleagues compared joint replacement in RA and OA in two databases. The National Data Bank for Rheumatic Diseases (NDB) helped the team compare whether people felt better or worse in terms of quality of life and pain. Because the NDB sends out questionnaires every six months to gauge the impact of rheumatic disease, the team could track the personal and financial burden of RA in thousands of patients. 

Michaud also examined the electronic medical records of more than 40,000 TJR patients in a Veterans Administration database for outcome data at 30 days and one year. These records allowed him to compare any problems with the surgery between OA and RA, such as infection, mortality and cardiovascular issues.

Most physicians, he says, would expect those issues to be worse in people with RA. Instead, Michaud’s team did not see a boost in risk for complications one month after surgery. At one year, RA patients showed an increase in mortality, but that was due to problems with the disease and not with joint replacement.

In people with OA, the improvement in pain relief proved more dramatic and lasted longer. For people with RA, joint replacement surgery turned back the clock on the replaced joint about three to five years, says Michaud.

Michaud did find an increase in return to the operating room for RA patients while they were in the hospital for joint replacement (4.5 percent for RA as compared to 3 percent for OA patients), although this was balanced by the finding that RA patients were less likely to return to the hospital in the two weeks after the surgery. Overall, he expected a much bigger difference between OA and RA patients.

“This was a welcome surprise,” he says.