QD Clinic: The Weight Behind Delay in Diagnosis Save

I'm Anthony Chan, rheumatologist from Reading, United Kingdom. And today I want to present to you a case entitled The Weight Behind the Delay.

I have a patient who has ankylosing spondylitis or sometimes also known as axial spondyloarthritis. He's male. He's in his early 30s and he had a body mass index, a BMI of 34. And in his history, he's had six years of low back pain. Now, this had been repeatedly called mechanical back pain due to his weight, due to his raised BMI. He had seen quite a few health professionals and clearly his scans showed there was some degenerative change in the discs in his back and therefore over time this was put down to being a mechanical cause. He also had slightly raised C-reactive protein or CRP and this again was put down to his obesity. In this case, the obesity delayed the diagnosis itself, not just the treatment.

He was then referred to the rheumatology clinic where I saw him having had six years of low back pain. On taking the history again, he presents with inflammatory back pain symptoms in his 20s. So he had typical symptoms of pain at rest, early morning stiffness lasting up to an hour. The pain was better on movement and worse with rest. And there was also nighttime waking. One of the key features that he suffered from was fatigue and again this was often put down to his obesity but he was never screened for sleep apnea which can be quite common in patients with obesity. The CRP looking back had been raised intermittently, not very high but above normal. Again, this was put down to his high body mass index.

On further investigation, he had a scan done, an MRI scan, but this time we included the sacroiliac joint and also the thoracic and cervical spine. Most of the musculoskeletal scans had only included the lumbar spine and the top part of the sacral joint, not the whole sacral joint. And these showed that there were inflammatory changes of axial spondyloarthritis. He subsequently had a HLA-B27 test and this was also positive.

Having already failed multiple anti-inflammatory drugs, NSAIDs, he was then screened and put onto a biologic treatment, a TNF inhibitor. And on review 12 weeks after treatment, he only had a partial response to treatment. And we know in this condition axial spondyloarthritis, we use scores such as the ASDAS and the BASDI to interpret treatment response. Now because of his obesity there were many other factors here that could have been affecting his ASDAS and BASDI. As you know these scores are very much patient reported and therefore there can be other factors including pain, fatigue, mood disturbances that often go with obesity that can affect the outcome measures that we use to assess treatment response.

So at this point I want to bring you to my clinic where we see him now at 6 months after he's been commenced on a TNF inhibitor and his BASDI remains high. His ASDAS also is high. His CRP has normalized but he doesn't feel great. He still feels very tired, fatigued. He feels low in mood and still has a lot of pain. So what would you do in this situation? Would you escalate his biologics or maybe consider a switch to his biologics or would you address the issue of weight, sleep and also deconditioning or would you do both in this situation.

Now we will come to what I did in a moment but we wanted to go back and look at the information regards to obesity. Now obesity is actually quite prevalent in axial spondyloarthritis. There are two studies. Firstly, the EUROSTAR study which had 14 countries and also the data from the Groningen cohort show that in up to 60% of patients with axial spondyloarthritis are either obese or overweight compared to sex-matched controls. And secondly, obesity predicts a poor TNF inhibitor response. In patients who are obese and on TNF inhibitor only a third of them achieve ASAS 40 compared to those who are within the normal weight. So therefore there is also the impact of the obesity on the treatment response to biologics such as TNF inhibitor.

Thirdly, the scores that we use namely ASDAS and BASDI are very much patient reported and we know that in obesity other factors such as chronic pain, fatigue and mood disturbances travel together with obesity. Hence, we have to match these scores with the CRP and also what we see on the MRI to ensure that these are measuring inflammation rather than non-inflammatory pain.

Now a lot of you would be familiar with the new concept of difficult to manage axial SpA but some of these patients I would say are more rather than difficult to manage, they're harder to treat axial SpA patients when there is also obesity and other comorbidities coexisting with the axial spondyloarthritis. What we need to do here is at the start of the treatment consider addressing these conditions referring them to weight management service and also to assess these patients in clinic. What can we do in clinic? Firstly of course measure their weight. You might want to measure their neck circumference or weight
waist circumference and there are scores that you can do in clinic to assess. Firstly for sleep apnea there is something called the STOP-BANG score and also the Epworth Sleepiness Score which can be used to look at daytime sleepiness and then you can use the FACIT-F score which is a way of measuring fatigue and these should be considered on top of the typical scores that we use namely BASDAI or ASDAS and when we have a fuller appreciation of this we may refer this patient to a sleep clinic for confirmation of sleep apnea as they may benefit from other treatments and also for weight management services to be involved with this patient, psychological services for their low mood and we can often use scores again to measure this and I think this is part of the whole holistic view that we have to have with patients who have obesity in the context of axial spondyloarthritis.

So my take-home from this patient is that while we are treating their inflammatory disease, we also need to consider some of the other non-inflammatory features that feature highly in patients with obesity, namely chronic pain, fatigue, and mood disturbances. The challenge for us is to disentangle them and to use the appropriate measures to understand this in order for us to have the best outcome for our patients. I'm Anthony Chan reporting here for RheumNow in this QD obesity clinic.