The findings presented today at the EULAR Conference suggest that, although biological therapy with tumour necrosis factor inhibitors (TNFi) may reduce the need for total hip replacement (THR) in older and more severe rheumatoid arthritis (RA) patients, no reduction was found in younger or less severe patients. Neither was there an association in rates of total knee replacement (TKR) or other joint replacement (OJR).
The study led by NDORMS researchers Samuel Hawley and Professor Daniel Prieto-Alhambra analysed data from over 11,000 patients recruited into the British Society for Rheumatology Biologics Registry for Rheumatoid Arthritis (BSRBR/RA) between 2001 – 2016.
The management of RA has progressed significantly over the last 25 years from providing relief of symptoms to regimens that impact disease activity. This evolution has been multi-factorial, however it is widely recognised that the introduction of biological therapy with TNFi in the late 1990s revolutionised treatment.
Recent research from the UK and Denmark has demonstrated a decline in the incidence of joint replacements for RA patients directly following the introduction of TNFi, yet the reasons for this decline are yet unclear. Understanding what is behind this trend could provide new avenues for managing joint replacement and improve patient care.
"The use of biologic therapies has been routinely offered as an explanatory factor for the reduction in rates of joint replacement over recent years," said lead researcher Samuel Hawley.
"Our study offers some support for this in that a reduction in hip replacement procedures was observed in older patients on TNFi, although our results also suggest additional factors are likely to be involved. For example, the drive for earlier diagnosis/treatment and increased prescription rates of conventional synthetic disease-modifying antirheumatic drugs".
In 2016, there were over 200,000 hip or knee replacements operations done in England, Wales and Northern Ireland. Despite their benefits, these operations pose various risks to patient health and incur significant healthcare costs, which for RA patients are approximately £6,000 - £7,000 per operation.
The study analysed the differences between RA patients who were TNFi or conventional synthetic disease-modifying antirheumatic drug (csDMARD) users in a 1:1 propensity score matched cohort of 19,116 patient records using the BSRBR/RA data. In the full study population, investigators found little evidence for an association between TNFi use and THR,TKR or OJR procedures. However, there was a significant reduction of THR by 40% in those over 60 years taking TNFi (HR 0.60 [CI:0.41-0.87]) and THR rate was cut by a quarter in TNFi users when analyses were restricted to more severe patients (DAS>5.1), although this didn't reach significance (HR 0.74 [CI 0.51-1.05]).
Samuel Hawley adds: "It's important to highlight that we used an observational study design and that despite our best efforts to address confounding factors, these may still partly explain our findings".