Rheumatoid arthritis patients who have undergone a hip or knee replacement are more likely to be readmitted to a hospital than are patients with osteoarthritis, according to findings from a large prospective registry study.
The analysis revealed an increasing trend in the incidence of 90-day readmissions in the rheumatoid arthritis (RA) patients by year, at 5.8%, 8.9%, and 10.6% for 2009, 2010, and 2011, respectively, Dr. Jasvinder Singh of the Birmingham (Ala.) VA Medical Center and his colleagues reported (Arthritis Care Res. 2014 Oct. 9 [doi:10.1002/acr.22497]).
For osteoarthritis (OA) patients, the 90-day readmission rates were similar by year at 6.7%, 6.7%, and 6.8%, respectively. After accounting for differences, including the risk by year, the adjusted risk for 90-day readmission in RA patients was 0.89 (95% confidence interval, 0.46-1.71) in 2009, 1.34 (95% CI, 0.69-2.61) in 2010, and 1.74 (95% CI, 1.16-2.60) in 2011, compared with OA patients.
Readmission after an elective hip or knee replacement is a problem of significant public health proportions, the study authors noted. A 90-day readmission rate of 6.8% translates to more than 70,000 admissions annually in the United States, they said.
The investigators analyzed 34,311 joint replacement procedures during the 3-year period – 33,815 performed in OA patients and 496 in patients with RA.
Overall, 42 RA patients were readmitted over the 3-year period, and the two most common reasons for readmission were joint prosthesis infection (10.2%) and septicemia (10.2%). For the 2,277 OA patients who were readmitted, the most common reasons were joint prosthesis infection (5.7%) and other postoperative infections.
The finding of an increasing 90-day readmission over a 3-year period in RA patients was a particular concern. “We considered several patient, procedure, surgeon, and hospital variables as important covariates and adjusted for those that were significant (age, gender, American Society of Anesthesiologists category, and iron deficiency anemia) in our multivariable-adjusted model, indicating that the increasing readmission rate in RA patients is not explained by these variables,” they wrote.
The effects of medications and pre- and postoperative rehabilitation programs could have played a role in readmission rates in RA patients, but the authors did not have the information to analyze the impact of these factors.
No conflicts of interest were declared.