It might seem strange for me to be writing this. After all, I have spent such a large part of my life engaged in research into bowel function, you might think I should be celebrating the advances that have occurred and supporting current efforts to discover more.
Up to a point I am, but when I look back at how much our understanding of IBS has changed since the diagnosis was consolidated in Rome twenty five years ago, it may not seem that impressive. We still don’t have a definite cause for IBS, nor any effective treatment and diagnosis remains one of excluding other conditions.
The problem may be the diagnostic criteria. 25 years ago, a committee of IBS opinion leaders met in Rome. Their intention was twofold; firstly to agree nomenclature and diagnostic criteria so that clinical researchers throughout the world would know they were studying the same condition and second to help doctors make a confident diagnosis based on ‘positive’ diagnostic criteria. Support for this exercise came from the pharmaceutical companies, anxious to develop new drugs for a diagnostic target that everybody agreed on.
I felt honoured to be invited to be a member of that first Rome committee, but was soon dismayed by the process. Our task was what the chairman called a ‘Delphic’ exercise; The Irritable Bowel Syndrome was being defined, not so much by careful analysis of research, but by the opinions of around ‘12 good men and true’ (there were no women on the committee as I recall). I resigned after three months, expressing the view that the Rome diagnostic criteria would hold up research in IBS for the next 25 years.
2016 marks the completion of those 25 years. There have been four revisions of the Rome diagnostic criteria, creating four weighty tomes. The Rome Criteria have become part of the medical establishment and the organising ‘International Federation of Functional Gastrointestinal Disorders’ a worldwide institution. The success of Rome is due not so much due to academic effort as political will. The committee has decreed how IBS should be defined; so any new paper on IBS has to conform to that definition in order to be published. But if the diagnosis is not sufficiently representative of IBS, no amount of research will advance our knowledge of it.
Some might accuse me of being a ‘dog in a manger’, still seeking to justify the decision I made 25 years ago. But time has passed and with it the hubris of youth. With hindsight, I can see how The Rome Criteria has focussed attention and galvanised research into gut reactions. But let us examine what has been achieved in the last 25 years. We have, for example, realised the importance of an attack of gastroenteritis in instigating IBS. We have understood how small intestinal bacterial overgrowth (SIBO) might cause abdominal symptoms in an anatomically normal gut. We know the range of poorly absorbed fermentable foods that can trigger symptoms of bloating, pain and diarrhoea in a sensitive gut. And scientists have developed genomic techniques to investigate the role of the colonic microbiome in gastrointestinal illness. These developments have enhanced the management of IBS, but in many cases, the principle had been known for many years. The gaseous potential of beans and other poorly absorbed carbohydrates was being studied in the nineteen eighties, SIBO was discovered many years previously when surgeons constructed blind loops of intestine after gastric surgery for ulcers, post infectious diarrhoea was first described in the nineteen forties. The elucidation of the colonic microbiome might well constitute a breakthrough though its potential for the understanding and treatment of IBS has yet to be realised.
Although the pharmaceutical industry remains a crucial sponsor, the Rome process has not materially altered drug treatment for IBS. Many novel compounds have struggled to withstand the passage of time and the presence of side effects. There are indeed new drugs for diarrhoea, constipation and abdominal pain and for depression, but these do not represent a significant advance over pre-existing symptomatic treatments and there is still no effective treatment for the Roman concept of IBS.
Is this is a useful anniversary to suggest a paradigm shift. As I argued in my previous post, the more we discover about IBS, the greater the number of factors that are involved. It would therefore seem that symptoms do not so much represent a specific cause as a resetting of the bowel caused by an individual combination of influences; stress, diet, lifestyle, dysbiosis, immune hyperreactivity and physiological change.
So instead of focussing their attention on the single elusive mechanism or cause, clinical scientists may be better employed studying the interaction of these factors and the individual nature of IBS, while the pharmaceutical industry could investigate how a new analogue or antagonist might interact with diet and lifestyle.
Such models do not necessarily conform to the way medical research is conducted. Epidemiological research requires variables that can be defined and measured. Cellular studies and animal models of illness usually study a single factor compared with a blank or control under otherwise identical conditions. Randomised controlled trials of treatment usually compare a specific intervention with a blank in carefully matched populations of patients. It is uncommon for research methodology to investigate combinations of factors or treatments. Moreover, most measurements and interventions are carried out in populations and not individuals. Customised treatment is considered too diverse and cumbersome.
Are we anywhere near individualised treatments for IBS? If health care professionals are to deliver customised therapy, the answer must be no; we are a long way off. But if the patient can gain the independence and confidence to find a safe integration of therapies that works for them, then we could say that we are already there. So should the future for IBS be guided self management; more a collaborative process of self knowledge and motivational interviewing aimed at facilitating the right combination of adjustments in diet, lifestyle and symptomatic treatment to suit the individual with IBS?
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