Prevalence of irritable bowel syndrome: a community survey

Irritable bowel syndrome (IBS) is a common health problem affecting a substantial proportion of the population. Many individuals with symptoms of IBS do not seek medical attention or have stopped consulting because of disillusionment with current treatment options. Such patients may choose to re-consult with the advent of new therapies with a resulting impact on health services.

To generate reliable estimates of the prevalence of IBS by age, sex and symptom group.

Postal survey.

Patients selected from registers of eight general practices in north and west Birmingham.

Eight thousand six hundred and forty-six patients aged >or=18 years were randomly selected from practice lists. Selected patients received a questionnaire, which included diagnostic criteria for IBS. A second questionnaire, seeking more detailed information, was sent to those whose responses indicated the presence of IBS symptoms.

Of the 8386 patients surveyed 4807 (57.3%) useable replies were received. The community-based prevalence of IBS was 10.5% (6.6% of men and 14.0% of women). Overall the symptom profiles were characterised by diarrhoea (25.4%), constipation (24.1%) and alternating symptoms (46.7%). Over half (56%) of all patients had consulted their general practitioner within the past 6 months and 16% had seen a hospital specialist. A quarter of patients consulted more than twice and 16% were referred to secondary care; almost half were on prescribed medication. However, the majority of patients were self-treated. Less than half of those currently reporting symptoms of IBS according to the Rome II criteria had received a diagnosis of IBS. Reduced quality of life and a previous diagnosis of a stomach ulcer were identified as predictors of consultation.

Quality of life was significantly reduced in patients with IBS. There is a substantial burden on primary healthcare services despite over half of those with symptoms also self- medicating. The Rome II diagnostic criteria identified those most affected by their symptoms and are a valid clinical tool. Population-based health surveys will need to supplement the Rome criteria with questions aiming to identify patients formally diagnosed but whose symptoms are currently under control if prevalence is to be reliably estimated.