Irritable Bowel Syndrome - An Evidence-Based Approach to Diagnosis

B.D. Cash; W.D. Chey


Aliment Pharmacol Ther. 2004;19(12) 

In This Article

Summary and Introduction

Irritable bowel syndrome (IBS) represents one of the most common reasons for primary care visits and consultation with a gastroenterologist. It is characterized by abdominal discomfort, bloating and disturbed defecation in the absence of any identifiable physical, radiologic or laboratory abnormalities indicative of organic gastrointestinal disease. IBS is a costly disorder, responsible for significant direct and indirect costs to patients and society. Much of the cost attributed to IBS arises from the time and resources used to establish the diagnosis. Historically IBS has been viewed by many as a diagnosis of exclusion rather than as a primary diagnosis, and many patients with typical symptoms will undergo an extensive array of diagnostic tests and procedures prior to the eventual diagnosis of IBS.

Recent reviews addressing the management of such patients have cast doubt on the necessity for this degree of testing. Current best evidence does not support the routine use of blood tests, stool studies, breath tests, abdominal imaging or lower endoscopy in order to exclude organic gastrointestinal disease in patients with typical IBS symptoms without alarm features. Serological testing for celiac sprue in this population may eventually prove useful but validation of studies indicating an increased prevalence of this disease in patients with suspected IBS is needed.

The development and refinement of symptom-based criteria defining the clinical syndrome of IBS has greatly facilitated the diagnosis of this condition, which can be confidently diagnosed through the identification of typical symptoms, normal physical examination and the exclusion of alarm features. The presence of alarm features or persistent non-response to symptom-directed therapies should prompt a more detailed diagnostic evaluation dictated by the patient's predominant symptoms.

Irritable bowel syndrome (IBS) is a chronic gastrointestinal condition characterized by abdominal discomfort, bloating and disturbed defecation. It is considered one of a group of functional gastrointestinal disorders in which a variety of factors including altered motility, abnormal visceral sensation and psychosocial factors interplay to cause symptoms. By definition, IBS is characterized by the absence of any identifiable physical, radiologic or laboratory abnormalities indicative of organic disease. IBS is a common condition, with prevalence estimates ranging between 7 and 24% in women and between 5 and 19% in men in the United States and Britain.[1,2,3] The symptoms of IBS represent one of the most common reasons for primary care visits, and consultation with a gastroenterologist accounting for 2.4-3.5 million physician visits per year.[1,4] Patients with IBS visit their physicians more frequently than those without IBS for both GI-related and non-GI-related problems, reflecting the increased likelihood of a variety of other conditions such as migraine headache, fibromyalgia and chronic pelvic pain.[5,6]

Based upon these observations, it should come as no surprise that the annual economic consequences of IBS in the United States are substantial. It has been estimated that IBS accounts for $1.7-10 billion in annual direct medical costs in the USA.[7,8] Perhaps more importantly, an additional $10-20 billion in indirect costs, largely resulting from work absenteeism and decreased productivity, has been attributed to IBS.[8,9] These estimates do not include prescription or over the counter-medications for IBS, so it is likely that a substantial portion of these costs may be attributed to the diagnostic testing that is frequently conducted as part of the evaluation of patients with suspected IBS. This paper will examine the current recommendations for the diagnostic evaluation of patients with suspected IBS and will critically review the evidence regarding the yield of various diagnostic tests and procedures that are routinely performed in this group of patients in order to exclude organic disease.


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