The use of tumor necrosis factor inhibitor (TNFi) therapy has not shown an association with rates of joint replacement in those with rheumatoid arthritis (RA), according to a study recently published in Rheumatology. Among older individuals, however, TNFi use corresponded to a 40% lower rate of total hip replacement.
This study included 19,116 participants from the British Society for Rheumatology Biologics Registry. Users of TNFi were matched 1:1 with users of standard synthetic disease-modifying antirheumatic drugs (DMARD) through propensity score estimation. Follow-up was administered through the use of physician questionnaires sent to participants’ clinics. The effect of TNFi on the first occurrence of total knee or hip replacement was analyzed using weighted multivariable Cox regression. Baseline disease acuteness and age were investigated for potential influencing roles.
The incidence of total hip replacement was not significantly associated with either the use of TNFi or standard synthetic DMARD (hazard ratio [HR], 0.86; 95% CI, 0.60-1.22; P =.39). The same results were noted for total knee replacement (HR, 1.11; 95% CI, 0.84-1.47; P =.46). However, age was a significant effect modifier on total hip and knee replacement (P <.001). Participants older than 60 years using TNFi were significantly less likely to undergo total hip replacement (HR, 0.60; 95% CI, 0.41-0.87; P =.008).
Limitations to this study included a higher disease severity among users of TNFi, possible confounding in the instrumental variable approach, a lack of generalizability due to the propensity scores analytical approach, and a somewhat long duration of disease at the start of the study.
The study researchers conclude that they “found no overall association between TNFi vs csDMARD therapy and subsequent incidence of joint replacement among [rheumatoid arthritis] patients, although a 40% relative reduction in [total hip replacement] rates was found among older patients. Future studies are needed to confirm and/or further elucidate the relationship between TNFi use and joint replacement.”
Some authors report financial associations with pharmaceutical companies. For a full list of author disclosures, please see original article.
Hawley S, Ali MS, Cordtz R, et al. Impact of TNF inhibitor therapy on joint replacement rates in rheumatoid arthritis: a matched cohort analysis of BSRBR-RA UK registry data [published online January 10, 2019]. Rheumatology. doi: 10.1093/rheumatology/key424