Understanding the Risk of Joint Replacement in Patients With Rheumatoid Arthritis

Disease-modifying antirheumatic drugs have reduced the need for total knee and hip arthroplasties (TKA and THA) in patients with rheumatoid arthritis (RA). However, there is still a far greater long-term risk of undergoing THA or TKA in patients with RA compared with patients who do not have RA, according to a study published in The Journal of Arthroplasty.

Since 1991 the proportion of patients with RA who are required to undergo TKA has dropped from 21.0% to as low as 2.4%. However, the few previous studies have been based on populations in the United States and Europe.

“Patients with RA who experience joint destruction, intractable joint pain, or unacceptable functional decline usually require joint arthroplasty,” the authors explained.

Researchers conducted a large-scale retrospective cohort study of 32,949 patients in Taiwan who were diagnosed with RA from 2000 to 2012. They were matched with 32,949 non-RA controls. Patients with RA had a more unfavorable Charlson comorbidity index score.

After adjusting for demographics and comorbidities, patients in the RA cohort had a 4.02-fold higher risk of undergoing TKA or THA (95% CI, 3.67-4.41). Factors that significantly increased the risk of THA or TKA were increasing age, living in an area of low urbanization, working as a manual laborer, 1 point in CCI score, having hypertension, or having gout.

Using multivariable stratified analyses, the researchers found that patients younger than 40 years actually had the highest risk of THA or TKA (adjusted hazard ratio, 43.18; 95% CI, 16.01-116.47). “Careful interpretation of the results is needed because of relatively small sample size of this age interval,” the authors noted.

However, they did note a previous study had shown young-onset RA was correlated with reduced radiographic progression and better functional score after 3 years. Those findings taken with the findings from the current study “suggest that despite the better short-term outcome, patients with young-onset RA are still more at risk of undergoing TKA and THA compared with patients with late-onset RA,” the authors wrote.

Based on the actual surgical procedures performed, patients with RA had a 4.56-fold higher risk of requiring THA, a 3.85-fold higher risk of TKA, and a 19.39-fold higher risk of requiring both THA and TKA compared with the non-RA cohort.

“We recommend that future researchers can include more detailed documented dose or regimen of DMARDs utilization to verify the dose–response effect in reducing the THA or TKA in RA patients,” the authors concluded.

Reference

Lee Y-H, Ko P-Y, Kao S-L, Lin M-C, Cheng-Chung Wei J. Risk of total knee and hip arthroplasty in patients with rheumatoid arthritis: a 12-year retrospective cohort study of 65,898 patients. J Arthroplasty. Published online July 2, 2020. doi:10.1016/j.arth.2020.06.085