— The use of TNF inhibitors may reduce the need for total hip replacement among older and more severe rheumatoid arthritis patients; however, no link was observed among younger or less severe patients, according to findings presented at the EULAR Annual Congress.
“Over 200,000 joint replacements for hip and knee took place in England, Wales and Northern Ireland in 2016; approximately [1% to 2%] of these would have been for inflammatory arthritides, such as rheumatoid arthritis,” Samuel Hawley, a DPhil/PhD student from the Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences at the University of Oxford, said during a press conference.
“The good news is that we know that there has been a decline over recent years in the incidence of knee replacement in RA in the UK, with an almost identical trend in knee replacement declines in RA in Denmark,” Hawley noted. “But why is this? Previous studies have inferred some role to the introduction of biologic therapies in the late 1990s and early 2000s, which revolutionized the management of RA; however, during the same time period, standard synthetic DMARDs have been used much more intensively and aggressively with an emphasis on earlier treatment.”
To evaluate the impact of either TNF inhibitor or conventional synthetic DMARD use on subsequent need for total hip replacement, total knee replacement or other joint replacement in patients with RA, Hawley and colleagues analyzed a propensity score matched cohort (n = 19,116) using the British Society for Rheumatology Biologics Registry for Rheumatoid Arthritis (BSRBR/RA) data.
The researchers matched all patients who received TNF inhibitors to patients receiving conventional synthetic DMARDs using a 1:1 ratio, and proceeded to weighted Cox regression to approximate the influence of TNF inhibitors on study outcomes.
Although the use of TNF inhibitors may reduce the need for total hip replacement among older and more severe rheumatoid arthritis patients, no such association was found among younger or less severe patients, according to recent findings.
According to study results, there was no significant association between TNF inhibitor use and total hip replacement or total knee replacement, with a total hip replacement rate of 6.3/1,000 patient-years (95% CI, 4.24-9.76) in the conventional synthetic DMARDs cohort and 5.22/1,000 patient-years (95% CI, 4.66-5.88) for TNF inhibitor cohort. Additionally, the rate for total knee replacement was 8.09/1,000 patient-years (95% CI, 5.32-12.89) for DMARDs and 8.89/1,000 patient-years (95% CI, 8.13-9.72) for TNF inhibitors.
“However, when we drill down and studied different age groups, we found that for the under 60-year-old patients, the results were essentially the same — with no difference in hip replacement rates between biologics and non-biologic users — but for the over 60-year-old patients, there was a 40% reduction in hip replacement rate associated TNF inhibitor use.”
Hawley noted that despite this significant reduction in hip replacement rates, this outcome was not replicated for the knee, with no significant differences in knee replacement rates for elderly patients between the two groups.
“Although there was no association overall with joint replacement rates and TNF inhibitor use, for older patients, there was a significant reduction in hip replacement with TNF inhibitors. Of course, this is an observational study and further studies are definitely required,” Hawley said. – by Bob Stott
Hawley S, et al. Abstract #OP0116. EULAR Annual Congress; June 13-17, 2018; Amsterdam.
Disclosure: Hawley reports no relevant financial disclosures. Please see the studies for all other authors’ relevant financial disclosures.