New Treatments Needed For Irritable Bowel Syndrome

The Comment is authored by Professor Robin Spiller, Wolfson Digestive Diseases Centre, University Hospital Nottingham, UK.

He says: “IBS is one of the commonest reasons for a consultation. However, because the disorder is poorly understood, many doctors find patients with IBS difficult to treat.

“Although extra time and effort may be needed, successful management is rewarding because it can substantially improve quality of life.”

IBS has a similar incidence in Europe and the USA, and is increasingly recognised in developing countries, with between 5-10% of the population estimated to be affected.

Patients who present with IBS are typically female, aged 20-40 years. Most patients have abdominal pain or discomfort intermittently, with flares of pain lasting two to four days. Other symptoms include bloating, abnormal stool frequency and abnormal defecation.

IBS is also associated with psychological distress, with 50% of IBS patients who seek medical care also suffering stress or anxiety. IBS patients also have substantially increased health-care costs, with patients consulting their primary-care physician twice as often as non-IBS patients. A third of IBS patients are referred to secondary care and also onto sometimes unnecessary specialties.

Professor Spiller says: “Most IBS patients require reassurance, explanation and lifestyle advice.”

The effects of modifying the diet of IBS sufferers is uncertain – trials have shown systematic exclusion of certain foods (e.g. wheat, dairy products) helped around half the patients in an uncontrolled trial, but how much of this was placebo response was unclear.

Psychological treatments have helped patients cope with IBS but generally without improving their bowel symptoms. Hypnosis has proven beneficial is randomised trials, including the long term, but limited availability of this treatment is a major drawback.

Most doctors and most (but not all) patients prefer to use drug therapy, ranging from antispasmodics to treat pain to serotonin antagonists to combat urgency and diarrhoea, and soluble fibres to improve pain and bowel habit. Tricyclic antidepressants can also prevent pain especially where diarrhoea is one of the symptoms present. But true drug effects in trials (10-15%) were smaller than the placebo effect (40-50%).

Professor Spiller concludes: “There remains a substantial unmet need for more effective remedies for IBS.”