Published: 13 August 2024
Assessing the type of pain experienced could unveil a more streamlined approach to treat people living with persistently painful rheumatoid arthritis, according to a trial by researchers at City St George’s, University of London.
This new approach could give patients the treatment that is most effective for them much sooner, without needing to trial multiple drugs.
Rheumatoid arthritis is an autoimmune disease where the immune system incorrectly attacks cells that line the joints, causing them to become swollen, stiff and painful. It’s a common condition estimated to affect around 400,000 people in the UK and 1-2 per cent of people worldwide.
Rheumatoid arthritis is treated by drugs called disease-modifying antirheumatic drugs (DMARDs) that work by lowering levels of inflammation in the body. People living with the condition often need to try various DMARDs - some of which are very expensive - until they find one that has a benefit. But many still experience significant and sustained pain.
In these cases, the sustained pain can be due to different causes - neuropathic pain where there is damage to the nervous system, nociceptive pain due to damage of other tissues (such as the joint tissue) or nociplastic pain where the nerves mistakenly tell the brain there is a painful threat.
Unaddressed issue in rheumatoid arthritis
“Pain control remains an unaddressed issue for many people with rheumatoid arthritis and we now need a paradigm shift in how doctors address this chronic pain in the clinic. My team are leading the field in understanding these different types of pain and we believe treating by the type of pain a person has is the key to faster and better care.”
- Professor Nidhi Sofat, trial lead and Professor of Rheumatology at City St George’s -
A total of 25 people living with painful rheumatoid arthritis who had already been prescribed DMARDs to reduce inflammation were recruited to the trial. They were randomly selected to receive one of two injectable ‘biologic’ drugs that target different elements of the immune system, and different types of pain, but are further down the order of drugs typically given to patients. Thirteen people received adalimumab, which switches-off the protein TNF and is the second or third line drug, and 12 people received abatacept, a fourth or fifth line drug that works by blocking T cells to reduce damage.
Measuring the type of pain
Over the 12-month study, the team performed pain assessments on all participants in rheumatology clinics at St George’s University Hospitals NHS Foundation Trust. Every three months patients underwent quantitative sensory testing to determine their pain pressure threshold by measuring changes in sensitivity to different types of sensations of various joints, different pain scales were used to determine their type of pain, blood tests measured signs of inflammation, and questionnaires were completed to assess physical function and emotional wellbeing.
After 12 months on abatacept or adalimumab, all pain scores and pain threshold improved, with the abatacept group showing the greatest improvements to pain sensitivity.
Levels of anxiety and depression were also measured. Abatacept was associated with a greater reduction in anxiety and depression scores, whilst the adalimumab group had no changes but remained at average levels that were consistent to the start of the trial.
All patients had elements of inflammatory, nociplastic and neuropathic pain but remained in remission at the end of the trial and continued treatment with the drugs after the study.
“We’ve established that it is feasible to measure for different types of pain in our clinics, so we can use that information to determine which rheumatoid arthritis patients need which type of treatment. If we can streamline treatment in this way from the get-go then it would remove patients’ stress of trialling differing drugs and get the right drug in the patient first time, whilst also cutting health costs.”
- Dr Liban Ahmed, first author and Academic Clinical Fellow at City St George’s -
The researchers note that recruitment was lower than expected as the trial took place during the Covid-19 pandemic. They now hope to build on this feasibility study to implement these thorough pain assessments in rheumatoid clinics across the UK in a nationwide clinical trial, where they also hope to investigate the impact of other drugs including newer biologics.
The study was funded by Bristol Myers Squibb and supported by the NIHR Clinical Research Network, with the results published in Pilot and Feasibility Studies.
Learn more about pain research at St George's