Background/Purpose: Total joint replacement (TJR) is performed when severe large joint destruction causes functional disability in patients with rheumatoid arthritis (RA). Biologics were approved in Japan for use in patients with RA in July 2003. We hypothesized that newer medications including biologics and more aggressive treatment strategies to suppress disease activity might have led to a delay in TJR in patients with RA. This study aimed to examine time trends in the characteristics of patients with RA undergoing primary TJR since the approval of biologics, and to determine factors associated with time from RA onset to TJR.

Methods: A total of 403 large joints (266 knees, 89 hips, 40 elbows, 5 shoulders, and 3 ankles) in 282 patients who underwent TJR at our institute between January 1, 2004 and December 31, 2017 were retrospectively examined. Time trends over the study period were assessed using the Jonkheere-Terpstra trend test for continuous variables and the Cochran-Armitage trend test for categorical variables. Moreover, patients were divided into two groups according to year of surgery: 2004-2010 and 2011-2017. Data at the time of surgery were compared between the two groups with the Mann-Whitney U test for continuous variables and the chi-square test for categorical variables. Multiple regression analysis was performed to assess whether serum C-reactive protein (CRP) levels at surgery and age at RA onset were associated with time from RA onset to TJR, with sex as an additional variable.

Results: A significant decreasing trend was observed in the number of TJRs performed from 2004 to 2017 (P =0.013) (Fig. 1). Both age at surgery and age at RA onset showed a significant increasing trend (P =0.002 and 0.034, respectively) (Fig. 2A). Time from RA onset to TJR showed no significant trend (P =0.294) (Fig. 2B). Serum CRP levels showed a significant decreasing trend (P < 0.001) (Fig. 2C), and the proportion of subjects with negative CRP (defined as ≤0.3 mg/dl) showed a significant increasing trend (P < 0.001) (Fig. 2D). Relative to the 2004-2010 group (n =234), the 2011-2017 group (n =169) was more likely to be older at surgery [median (IQR), 66 (60-73) vs. 63 (57-69) years, P =0.005], older at RA onset [51 (41-61) vs. 48 (37-57) years, P =0.013], have lower serum CRP levels [0.30 (0.07-0.95) vs. 0.88 (0.29-2.22) mg/dl, P < 0.001], and have a higher rate of negative CRP (50% vs. 27%, P < 0.001) (Table 1). With respect to RA treatment, a significant increasing trend was observed in the proportion of subjects receiving MTX (P =0.004) and biologics (P < 0.001) (Figs. 2E, 2F). Multiple regression analysis revealed that negative CRP [partial regression coefficient (B) =1.56, P =0.046] and age at RA onset (B =-0.51, for a 1-year increase, P < 0.001) were independently associated with time from RA onset to TJR.

Conclusion: The number of TJRs decreased since the approval of biologics in Japan, and changes were observed in the characteristics of RA patients undergoing TJR. Negative CRP, defined as ≤0.3 mg/dl, was associated with longer times from RA onset to TJR independently of age. Newer medications and more aggressive treatment strategies to suppress disease activity can reduce the number of and delay TJR in patients with RA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/characteristics-of-patients-with-rheumatoid-arthritis-undergoing-primary-total-joint-replacement-a-14-year-trend-analysis-2004-2017/