Continuous NSAID offers no benefit over on-demand in ankylosing spondylitis

More evidence is needed to confirm whether continuous NSAID can reduce joint damage in people with ankylosing spondylitis.

INTRODUCTION
Ankylosing spondylitis is a chronic inflammatory disease. It mainly involves the joints, but may be associated with other diseases, such as psoriasis (a skin disease), inflammatory bowel disease and uveitis (an inflammation in the eye). These non-joint symptoms are known as extra-articular manifestations and they may arise from the same underlying causes, typically inflammation in the body. Patients can also be classified as having axial or non-axial (peripheral) disease, according to which joints in their body are affected. Axial disease affects the sacroiliac joint (in the back part of the pelvis) and the spine, causing back pain and stiffness. Diclofenac is a non-steroidal anti-inflammatory drug (also called NSAIDs). It is given to people with ankylosing spondylitis to reduce inflammation and control pain.

WHAT DID THE AUTHORS HOPE TO FIND?
An earlier study suggested that NSAIDs can inhibit new bone formation in the spine and prevent long-term bone damage and disability in people with ankylosing spondylitis. The authors wanted to confirm whether this was true by repeating the study with diclofenac – a different type of NSAID.

WHO WAS STUDIED?
The study looked at 85 people with ankylosing spondylitis whose symptoms justified being prescribed diclofenac for 2 years.

HOW WAS THE STUDY CONDUCTED?
This was a randomised prospective study that took place in 19 clinics in Germany from 2008 to 2013. People who agreed to take part were assigned by chance to one of two groups. Using chance in this way means that the groups will be similar and will allow the variable under investigation to be compared objectively. The first group was treated with the highest possible dose of diclofenac (150 mg) and had to take it every day (continuous treatment). If people had side effects they could change the drug or reduce the dose, but not to less than 75 mg a day. The second group could take diclofenac according to their symptoms (on demand treatment).

WHAT WERE THE MAIN FINDINGS OF THE STUDY?
After 2 years, there was no evidence on X-ray of any difference in structural damage or new bone formation of the bone in the spine between the two treatment groups. The authors could not confirm the earlier study results that suggested that continuous use of NSAIDs might prevent new bone formation.

ARE THESE FINDINGS NEW?
Yes, these findings are new, but they are in contrast to earlier findings from other studies.

HOW RELIABLE ARE THE FINDINGS?
The number of patients being investigated was quite small, but the authors are confident that the results obtained in this study are solid and reliable.

WHAT DO THE AUTHORS PLAN ON DOING WITH THIS INFORMATION?
In this study, over 70% of the people stayed on diclofenac for the whole 2 years, and did not change to another NSAID. In the earlier study most people were treated with another NSAID called celecoxib. It should therefore be further investigated in future studies whether the difference seen in the study results is due to the effects of different NSAIDs.

WHAT DOES THIS MEAN FOR ME?
If you have ankylosing spondylitis, your NSAID treatment should be guided by your symptoms. Treatment with NSAIDs should be stopped or reduced if you are in remission (free of symptoms). It is important that you do not stop treatment yourself without talking to your doctor.

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Date prepared: August 2016

Summary based on research article published on: 4 August 2015

From: Sieper, J. et al. Effect of continuous versus on demand treatment of ankylosing spondylitis with diclofenac over 2 years on radiographic progression of the spine – results from a randomized multi-center trial (ENRADAS). Ann Rheum Dis 2016;75:1438–43.

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