Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders encountered in general practice. In the general UK population, 17% of adults report symptoms of IBS over the previous 12 months and a quarter have consulted their GP at some time.
Both symptoms and consultations are more common in women. IBS is a chronic disorder, with the majority of patients still symptomatic after 5 years. Although 80% of patients are managed without referral to specialist care, the disorder remains the most common reason for referral to gastroenterology clinics.
IBS is a benign disorder that does not predispose to more serious disease, but it can have a major impact on social functioning and quality of life.
Aetiology and diagnosis
IBS is a common condition characterised by abdominal pain and disturbance of bowel habit in the absence of an identifiable structural or biochemical disorder. The bowel disturbance may be diarrhoea or constipation or a mixed type.
Expert groups have developed explicit criteria for the diagnosis of IBS over the years, the most recent being the Rome II criteria1 (Table 1, below). These criteria are not widely used in general practice, although the correlation between GP diagnoses and the Rome II criteria is about 70%.
|Table 1: The Rome II criteria for diagnosis of IBS|
Abdominal discomfort or pain for 12 weeks or more in the preceding 12 months that has two of the following three features:
The following symptoms cumulatively support the diagnosis of IBS:
The underlying abnormality in IBS is visceral hypersensitivity, such that sufferers experience gastrointestinal tract discomfort at a lower threshold of stimulation than do non-sufferers.
Psychological problems play a part in modifying gut responses and these patients are also more likely to consult a doctor. However, most patients with IBS who consult their GP do not have major psychological problems.
An important factor in the development of IBS is acute gastrointestinal infection. Up to 20% of patients relate the onset of symptoms to such an event.
Current issues in IBS
For GPs the patient with IBS represents a series of challenges. The first is the patient's anxiety, sometimes shared by the doctor, that there is a serious cause for the symptoms.
This can be compounded by the remitting and relapsing nature of symptoms, their association with psychological stresses, and the limited benefit of drug therapies.
On the face of this it can sometimes prove difficult for the patient to maintain confidence in the diagnosis and the doctor's management. As a result they embark on a lengthy, and of course ultimately fruitless, process of diagnosis by exclusion.
At the same time the GP is prevailed upon to exercise restraint in the referral of any patients who do not have high-risk features for colorectal cancer or inflammatory bowel disease.2
The effectiveness of drug treatments in IBS is dogged by high placebo rates and the intermittent nature of symptoms. Nevertheless, antispasmodics remain the mainstay of treatment. In recent years the benefits of tricyclic antidepressants have been recognised, and much current research interest is focused on drugs acting on the 5HT3 and 5HT4 receptors in the gut.
Aims of the guideline development group
There has been a surge of interest in IBS and its management in recent years. The increasingly open debate between primary and secondary care on the use of the referral process, given even greater focus by the resource pressures of the 2-week rule for suspected cancer, together with the development of new therapeutic approaches to IBS, lie behind this.
Finally, in 2000 the British Society of Gastroenterology published its own guideline for the management of IBS3 (see also Guidelines in Practice 2001; 4(3): 25-30). This highly detailed and extensively referenced work – so long it is sometimes referred to as a 'guidebook' – was recognised as a valuable contribution to the care of patients with IBS, although from a largely secondary care perspective.
The Primary Care Society for Gastroenterology has in recent years published a series of clinical guidelines that are deliberately concise, accessible and patient-centred, and which address the issues encountered in general practice. With IBS, it recognised another important clinical problem that needed to be addressed in the same way.
We used a consensus group approach to develop a clinical guideline on the diagnosis and management of IBS in primary care. A multidisciplinary group was formed, comprising gastroenterologists with a special interest in IBS, GPs, nurses and a counsellor associated with the IBS Network, an independent self-help group for sufferers.
The group was briefed on the Society's previous guideline development work, and the goals of this project. At the first meeting we identified the key issues that needed to be addressed and the questions that would need to be answered by a review of the literature.
The project team, based in the departments of general practice at Guy's, King's and St Thomas' and at the University of Sunderland, then developed a detailed and systematic literature search strategy. This was applied to the MEDLINE, EMBASE and PsycINFO databases from 1984, producing 2630 abstracts, which were then scanned for relevance, reducing them to around 600.
All these papers have been assessed for quality, relevance and findings using the stringent methodology of the Cochrane review process.
Much of the evidence is of low quality and many of the therapeutic trials are from secondary care, where patients are more likely to believe that they have organic disease and are more resistant to reassurance and non-pharmacological therapies.
Recommendations were formulated in response to the questions that had been identified, and were considered and refined by the group. The resulting draft guideline was then sent to a wider group of colleagues for peer review before publication.
Recognising the difficulty in making a secure diagnosis, the guideline identifies alarm symptoms, the approach to investigation and possible alternative diagnoses. It stresses the importance of the early consultations in addressing patients' fears and concerns.
It then identifies the individual symptoms of IBS for which high-level evidence exists for benefit from individual drugs (Table 2, below). Other,non-pharmacological therapies are also discussed with the evidence for their effectiveness.
Table 2: Evidence grading of treatments for irritable bowel syndrome
|Low dose tricyclic antidepressants||Ib||Ib|
*Conflicting evidence of benefit **Study conducted in primary care
How will the guideline improve patient care?
The guideline seeks to support the decision making of GPs and others who provide primary care to patients with IBS.
General practice care is characterised by a holistic doctor-patient relationship that is sustained over time. An effective doctor-patient relationship is the key to managing IBS. The early consultations, in which a positive yet safe diagnosis is made, fears addressed and psychological factors explored, are all-important.
The fear of wrongly diagnosing serious disease such as colorectal cancer or inflammatory bowel disease is an important concern for GPs. This has to be balanced against a wish for the patient's sake to keep unpleasant investigations to the minimum and to use secondary care resources prudently. The guideline aims to support positive diagnosis while alerting the clinician to alternative clinical possibilities that may need further investigation.
Drug therapies are of limited value in IBS, with placebo response rates of the order of 40%. The guidance on therapies can help to ensure that drugs are accurately targeted at the dominant symptoms, and that non-drug therapies are considered where appropriate.
The guideline is to be published in full later this month (September 2001), and will also be available on the PCSG wesite (see Box 1, below). It will be considered for review in 2003.
|Box 1: Sources of further information|
- Thompson WG, Longstreth G, Drossman DA et al. Functional bowel disorders and functional abdominal pain. Gut 1999; 45(Suppl 2): II43-7.
- Referral Guidelines for Suspected Cancer. Department of Health, April 2000.
- Jones J, Boorman J, Cann P et al. British Society of Gastroenterology guidelines for the management of irritable bowel syndrome. Gut 2000; 47(Suppl II): II1-19.