I want to discuss remission as it pertains to IBD. Remission is the goal of every patient and every treatment plan. The terminology can get confusing because there are a few different types of remission. The goal is to familiarize you enough with these terms and not confuse you, also it is important to know that these terms are not always used by clinicians, research trials, and scientists. Each group might use one and not the other but I will cover all of them and if you come across them you will already know the meaning. My next blog post is covering a clinical trial and they use some of these terms, which is a reason I am writing this. All of this information is backed by legitimate research papers that I am using as my guide which I will link to at the end of the post. Let’s first start with what is remission?
What is Remission?
Inflammatory Bowel Disease, unfortunately, has no cure but what we do have are very advanced treatment options that can allow us to get into what is called remission. Remission, in this case, is a broad term that means the disease is under control and the patient is feeling well but the term remission can be broken down even further. There are many terms used when it comes to remission such as; Clinical Remission, Mucosal Healing, Endoscopic Remission, Histological Remission, Biochemical Remission and Deep Remission. I know it seems like a lot but some of those terms go together and I want to discuss each one a little further. Let’s start with clinical remission.
Clinical remission is used when the patient symptoms have improved to where they are not really noticeable and they are overall feeling well. However, clinical remission does not mean there is not any active disease or underlying inflammation. I know this can be confusing because of the word “remission” but it just refers to the symptom aspect of IBD and is the basic clinical assessment of the patient without using invasive tests (blood work, colonoscopy, EGD). A lot of IBD patients think that because their symptoms are better this must mean their disease activity is better as well. Unfortunately, this is not always the case because you can still have low levels of inflammation which can be damaging your Gi tract without having symptoms and for this reason your physician will do blood work to check inflammatory markers and routine colonoscopies even when you feel well. Let’s now look at Biochemical Activity.
Biochemical Activity is sometimes referred to Biochemical Remission if the patient’s biochemical tests are normal. I know the word “Biochemical” can seem scary but, in this case, Biochemical activity is referring to the inflammatory markers that are checked by a blood work or stool samples. I mentioned earlier that even though you are in clinical remission where you are symptom-free, you can still have underlying inflammation and active disease in the GI tract. This is where biochemical testing is needed. The blood or fecal tests check inflammatory markers such as white blood cell count, SED rate, fecal calprotectin etc. These are all markers that will show whether you have inflammation going on somewhere in your body and can tell your physician whether or not your clinical symptoms match your biochemical activity. The next step to determine if you are in remission is to check your GI tract for any sign of the disease which leads us to our next remission types.
When you have an endoscopy or colonoscopy your physician will take biopsies of the bowel tissue. They do this to check for inflammation called “leukocyte infiltration” in that area of the bowel. The sample is sent to pathology and they can do some staining that will allow them to see any inflammation or changes in the bowel tissue, which would let them know if you have active disease. There can be an issue with this when it comes to Crohn’s Disease because Crohn’s can be in any part of the GI tract and is patchy. The biopsy could show no inflammation, but then millimeters away there could be active disease. This, however, does not mean they won’t take samples, they will, because histological tests are important. Histological remission means that the biopsies they had taken showed no signs of inflammation or active disease. Histological remission is also uncommon with current therapies according to the research.
Endoscopic improvement & Mucosal Healing:
Although there is still no general consensus on the definition of the term mucosal healing, mucosal healing on endoscopy usually refers to the resolution of ulcers in CD and resolution of erosions and ulcers in UC. It is used in reference after you had a previous endoscopy, meaning previous endoscopies showed inflammation and ulceration, then you were put on treatment and follow-up endoscopies showed the ulcers were getting better, this is mucosal healing. I know I am being redundant but, once again this does not necessarily mean you don’t have any underlying inflammation and active disease you can still have inflammation and ulcers, it shows if the bowel wall is improving. Mucosal healing is actually a newer target for treatment and healing of the disease, not only in clinical practice but also in research trials. The paper states “The paper states “This was based on evidence that the long-term disease behaviour appears to be better when mucosal healing is achieved.” It is a visual term, as in what your physician sees with his eyes during your endoscopy. This term can also be called “endoscopic improvement.”
*Update: Recently there was a bit of an update to histological and mucosal healing. There was a new endpoint used for a drug clinical trial where they were looking for Histoendoscopic mucosal healing. This was a combination of seeing mucosal healing using endoscopy and also having histological healing so you could visual see improvement and then pathology showed little to no active inflammatory cells. It’s something that warrants further studies because it did not happen in evert patient within the trial and it could be that those with milder disease respond better and can get to this level of remission vs pulling someone off a therapy thats working to try to achieve the deeper level. Either way it’s a good stepping point and showing we have really effective treatments now that will only get better.
Deep remission is also a newer term being used for IBD patients and endpoint for some clinical trials.This type of remission encompasses all of the other terms. This means that the patient is in clinical remission meaning no symptoms, in biochemical remission meaning blood work and other inflammatory tests show no signs of inflammation, histological remission meaning the biopsies were clean, there is mucosal healing and endoscopic remission meaning no visual signs of disease in the GI tract. This is the remission we all strive to be in. Where it seems as if we are disease free and quality of life is not impacted. Deep remission is great, but it still doesn’t mean “cured.” This term might not be used that often either. There is always a chance of the disease recurring and it can take a long time to get a patient into any kind of remission, but just know it is possible and current treatments are advancing at a very fast pace.
* Histological remission is not used in the definition “Deep Remission” anymore because it is so hard to achieve today. Only 10-20% of patients achieve histological remission with current therapies. The FDA also just released s few days ago new information about specific remission end points in IBD trials. Like I mentioned this terminology is constantly changing but the point is to be familiar with these terms just in case you come across them. *
There are many terms when it comes to remission and IBD, some of them you may never see or come across and others you might see all the time. Remember, different research papers, clinical trials, physicians and scientists often do not use the same terminology which is why I discussed all of the remission terms I could find related to IBD. These terms are also still being debated and as a whole, are still trying to determine which ones should be used especially, when it comes to clinical trials. I hope this was an educational post and you learned something and did not leave more confused than when you started! My next blog post is regarding a new FMT clinical trial and they use some of these terms and this is the main reason I chose this topic. I hope you stick around for the next blog post as we cover the clinical trial!
Rogler, G., Vavricka, S., Schoepfer, A., & Lakatos, P. L. (2013). Mucosal healing and deep remission: What does it mean? World Journal of Gastroenterology, 19(43), 7552–7560. http://doi.org/10.3748/wjg.v19.i43.7552
Neurath, M. F. (2014). New targets for mucosal healing and therapy in inflammatory bowel diseases. Mucosal Immunology, 7(1), 6–19. http://doi.org/10.1038/mi.2013.73