Introduction of bDMARDs Linked to Reduced Incidence of Total Knee Replacement

The introduction of biological disease-modifying antirheumatic drugs (bDMARDs) has been associated with a decreased incidence rate of total knee replacement (TKR) in patients with incident rheumatoid arthritis (RA), according to an interrupted time-series analysis published in the Annals of the Rheumatic Diseases.¹

Between 1996 and 2011, researchers in Denmark identified 30,404 patients from the Danish National Patient Register with incident RA as well as 297,916 general population comparators.¹ They found that in 1996, the 5-year incidence rate of total hip replacement (THR) and TKR among patients with RA was 8.72 and 5.87 respectively, and was 2.89 and 0.42 in the comparator group.  

In the pre-bDMARD era from 1996 through the end of 2001, there was a decreasing trend in the incidence rate of THR among patients with RA. Following a lag period in 2002 when bDMARDs were introduced, the incidence of THR continued to decrease at the same rate as observed in the pre-bDMARD era. For the general population comparators, the incidence rate of THR increased throughout the entire study period, but to a lesser extent after 2003.

The incidence rate of TKR increased in the pre-bDMARD era among patients with RA, but started to decrease after the introduction of bDMARDs. For the general population comparators, the incidence rate of TKR increased from 1996 to 2001, and increased to a lesser extent after 2003.

The trends in the incidence rates of THR and TKR identified in this study were similar to those found in other studies.^1-5

”The incidence rate of THR and TKR was 3-fold and 14-fold higher, respectively, among patients with RA compared with general population comparators in 1996,” the researchers wrote. They concluded that in patients with RA, introduction of bDMARDs was associated with a decrease in the incidence rate of TKR, but not of THR.¹

References

1. Cordtz RL, Hawley S, Prieto-Alhambra D, et al. Incidence of hip and knee replacement in patients with rheumatoid arthritis following the introduction of biological DMARDs: an interrupted time-series analysis using nationwide Danish healthcare registers [published online December 15, 2017]. Ann Rheum Dis. doi:10.1136/annrheumdis-2017-212424
2. Hawley S, Cordtz R, Dreyer L, et al. Association between NICE guidance on biologic therapies with rates of hip and knee replacement among rheumatoid arthritis patients in England and Wales: an interrupted time-series analysis [published online September 23, 2017]. Semin Arthritis Rheum. doi:10.1016/j.semarthrit.2017.09.006
3. Hekmat K, Jacobsson L, Nilsson JÅ, et al. Decrease in the incidence of total hip arthroplasties in patients with rheumatoid arthritis–results from a well defined population in south Sweden. Arthritis Res Ther. 2011;13:R67.
4. Louie GH, Ward MM. Changes in the rates of joint surgery among patients with rheumatoid arthritis in California, 1983-2007. Ann Rheum Dis. 2010;69:868-871.
5. Shourt CA, Crowson CS, Gabriel SE, Matteson EL. Orthopedic surgery among patients with rheumatoid arthritis 1980-2007: a population-based study focused on surgery rates, sex, and mortality. J Rheumatol. 2012;39:481-485.