Thousands of patients with an inflammatory arthritis condition might be being mis-diagnosed because the pain killers they take hide the problem from doctors.
A new University of Aberdeen study, funded by Arthritis Research UK, aims to see how big a role patients' medication plays in slowing down diagnosis of axial spondyloarthritis.
It is estimated around 700,000 people in the UK live daily with inflammatory back pain.
Most manage the pain with anti-inflammatory drugs such as Ibuprofen or other slightly stronger variants whilst they wait to have the condition formally diagnosed by a rheumatologist.
Axial spondyloarthritis is an inflammatory condition affecting the spine and joints in the pelvis and in extreme cases can lead to parts of the spine fusing together.
It is diagnosed using MRI scans after which it cannot be cured but can be managed with special anti-inflammatory medication.
Researchers behind the study suspect that some people who undergo an MRI scan receive a negative diagnosis for axial spondyloarthritis because the Ibuprofen-like drugs they are taking sufficiently reduce the inflammation and 'hide' the symptoms.
Early diagnosis is key to preventing axial spondyloarthritis getting worse but typically it can take between 8-11 years to be properly identified.
This study will give an indication as to what proportion of axial spondyloarthritis are mis-diagnosed as a result of the anti-inflammatory drugs.
Two hundred and fifty patients with the condition will be recruited to the study from around 20 different centres. They will stop taking their regular anti-inflammatory drugs (Ibuprofen, etc) for a week and then given an MRI scan. They will then start taking the drugs again for six weeks before receiving a second MRI scan.
The researchers will then compare the proportion of people who scanned positive for axial spondyloarthritis with those who scanned negative for the condition once they are back on them.
Lead researcher, Dr Gareth Jones, a musculoskeletal pain and spondyloarthritis expert, said: "The fact that it can take up to 11 years to get a formal diagnosis of axial spondyloarthritis is obviously a concern. There are good drugs to help people manage the condition but they are only available to people who get a correct diagnosis.
"We suspect some people who are getting scanned for the condition, who still have anti-inflammatory drugs like Ibuprofen in their system, are scanning negative for axial spondyloarthritis because the drugs are masking the true extent of the inflammation.
"This study aims to show whether or not these drugs do mask the condition, and what proportion of sufferers could potentially be affected. If we see that the pain killers are indeed leading to negative diagnoses then it will lend support to the argument that anyone receiving an MRI scan for back pain should halt their regular anti-inflammatory medication for a week or so prior to the scan."
Stephen Simpson, director of research & programmes at Arthritis Research UK, added: "Axial spondyloarthritis is an incredibly painful condition, which can have a devastating impact on a person's everyday life. For example, those with ankylosing spondylitis are three times more likely to stop work than the general population.
"This new research will prompt conversations around whether patients should be asked to refrain from taking non-steroidal anti-inflammatory drugs immediately prior to an MRI scan and to rely, instead, on other pain relief during this specific period. This research could lead to earlier diagnosis for people living with the condition, leading to earlier commencement of appropriate treatment and improved outcome."
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