Irritable bowel syndrome (IBS) is the most common functional disorder of the gastrointestinal tract. As a result of the lack of specific diagnostic testing and absence of circumscribed biologic markers of disease, the diagnosis is based on a constellation of symptoms. In an attempt to standardize the definition of disease, an international consensus group formalized clinical parameters based on data from Manning et al<sup>40 Manning A.P., Thompson W.G., Heaton K.W. , e al. Towards a positive diagnosis of the irritable bowel BMJ 1978 ;  2 : 653  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> for a symptom-based diagnosis. In reference to the location of the meeting, these criterion have been termed the Rome criteria and subsequently have been refined further (see the accompanying box).<sup>59 Thompson W.G., Longstreth G.F., Drossman D.A. , e al. Functional bowel disorders and functional abdominal pain Gut 1999 ;  2 (suppl) : 1143

Cliccare qui per andare alla sezione Riferimenti</sup> At present, because of incomplete understanding of the pathophysiology of IBS, patient subsets are defined by their predominant symptom (Figure 1).

Symptoms of IBS have afflicted humans since antiquity. Maimonides advised that humans should strive to have their intestines relaxed all the days of their lives. IBS is a common disorder affecting approximately 15% of the population.<sup>1 Agreus L. The epidemiology of functional gastrointestinal disorders Eur J Surg 1998 ;  583 (suppl) : 60

Cliccare qui per andare alla sezione Riferimenti</sup> One third seek medical attention from their primary physician, and 10% to 15% are referred to a gastroenterologist.<sup>47 Paterson W.G., Thompson W.G., Vanner S.J. , e al. Recommendations for the management of irritable bowel syndrome in family practice. IBS Consensus Conference Participants Canadian Medical Association Journal 1999 ;  161 : 154

Cliccare qui per andare alla sezione Riferimenti</sup> Based on the large portion of the population affected, the societal costs of the disease are immense. Physician visits total approximately 3.5 million a year, and medications are prescribed for most patients, averaging 2.2 million prescriptions a year.<sup>19 Everhart J.E., Renault P.F. Irritable bowel syndrome in office-based practice in the United States Gastroenterology 1991 ;  100 : 998

Cliccare qui per andare alla sezione Riferimenti, 23 Gralnek I.M. Health care utilization and economic issues in irritable bowel syndrome Eur J Surg 1998 ;  583 (suppl) : 73  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> In a comparative study in 1992 dollars, office-based costs averaged $742 per IBS patient compared with $429 for nonpatients.<sup>57 Talley N.J., Gabriel S.E., Harmsen W.S. , e al. Medical costs in community subjects with irritable bowel syndrome Gastroenterology 1995 ;  109 : 1736  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Pharmacologic costs are significantly greater in IBS patients.<sup>14 Drossman D.A., Li Z., Andruzzi E. , e al. US householder survey of functional gastrointestinal disorders Dig Dis Sci 1993 ;  38 : 1569  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Patients with IBS have a greater likelihood of suffering other medical and gastrointestinal problems.<sup>43 Mayer E.A., Fass R., Fullerton S. Intestinal and extraintestinal symptoms in functional gastrointestinal disorders Eur J Surg 1998 ;  583 (suppl) : 29-31

Cliccare qui per andare alla sezione Riferimenti</sup> For example, functional dyspepsia occurs in more than one third of IBS sufferers.<sup>56 Talley N.J. Scope of the problem of functional digestive disorders Eur J Surg 1998 ;  582 (suppl) : 35

Cliccare qui per andare alla sezione Riferimenti</sup> Patients with IBS are more likely to undergo surgery, including hysterectomies and appendectomies, and are more apt to have had multiple operations.<sup>38 Longstreth G.F., Preskill D.B., Youkeles L. Irritable bowel syndrome in women having diagnostic laparoscopy or hysterectomy: Relation to gynecologic features and outcome Dig Dis Sci 1990 ;  35 : 1285  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Evaluation and treatment of associated disorders and the greater tendency for additional surgery inflate health care costs further.

Indirect costs are more difficult to calculate but appear substantial. In one study, absenteeism over 1 year averaged 13.4 days for patients with IBS compared with 4.0 days for controls. The diagnosis and treatment of IBS and its associated problems account for billions of health care dollars.