Irritable bowel syndrome (IBS) is a functional condition of the bowel that is diagnosed using clinical criteria. This paper discusses the nature of the diagnostic process for IBS and how this impacts epidemiological measurements. Depending on the diagnostic criteria employed, IBS affects around 11% of the population globally. Around 30% of people who experience the symptoms of IBS will consult physicians for their IBS symptoms. These people do not have significantly different abdominal symptoms to those who do not consult, but they do have greater levels of anxiety and lower quality of life. Internationally, there is a female predominance in the prevalence of IBS. There is 25% less IBS diagnosed in those over 50 years and there is no association with socioeconomic status. IBS aggregates within families and the genetic and sociological factors potentially underlying this are reviewed. Patients diagnosed with IBS are highly likely to have other functional disease and have more surgery than the general population. There is no evidence that IBS is associated with an increased mortality risk. The epidemiological evidence surrounding these aspects of the natural history is discussed.

Summary Background Irritable bowel syndrome (IBS) is a chronic functional disorder of the gastrointestinal system affecting a large number of people worldwide. Whilst it has no attributable mortality, it has substantial impact on patients' quality of life (QoL) and is associated with considerable healthcare resource use. Aim To review the economic impact of IBS, firstly on the individual, secondly on healthcare systems internationally and thirdly to society. Methods Appropriate databases were searched for relevant papers using the terms: Irritable Bowel Syndrome; IBS; irritable colon; functional bowel/colonic disease; economics; health care/service costs; health expenditure/resources; health care/service utilisation; productivity. Results Irritable bowel syndrome impacts most substantially on patients' work and social life. Reduction in QoL is such that on average patients would sacrifice between 10 and 15 years of their remaining life expectancy for an immediate cure. Between 15% and 43% of patients pay for remedies. No studies quantify loss of earnings related to IBS. Direct care costs are substantial; 48% of patients incur some costs in any year with annual international estimates per patient of: USA $742–$7547, UK £90–£316, France €567–€862, Canada $259, Germany €791, Norway NOK 2098 (€262) and Iran $92. Minimising extensive diagnostic investigations could generate savings and has been shown as not detrimental to patients. Cost to industry internationally through absenteeism and presenteeism related to IBS is estimated between £400 and £900 per patient annually. Conclusions Irritable bowel syndrome is associated with substantial costs to patients, healthcare systems and society. Considerable benefit could be obtained from effective interventions.

SUMMARY BackgroundCrohn's disease is associated with small bowel cancer whilst risk of colorectal cancer is less clear.

SUMMARY AimTo perform a meta-analysis is of published literature reporting standardized mortality ratios (SMR) for Crohn's patients from 1970 to date. MethodsMedline search identified relevant papers. Exploding references identified additional papers. When two papers reviewed mortality of one patient group at different times, the later publication was used. ResultsOf 13 papers identified, three studies reported SMR below 1.0, two others had confidence intervals including 1.0. All other studies reported mortality higher than the general population. Meta-analysis using a random effects model shows the pooled estimate for SMR in Crohn's disease is 1.52 (95% CI: 1.32 to 1.74 [P < 0.0001]). Meta-regression shows the SMR for these patients has decreased slightly over the past 30 years, but this decrease is not statistically significant (P = 0.08). ConclusionAssessing evidence from original studies and conducting a meta-analysis shows age-adjusted mortality risk from Crohn's disease is over 50% greater than the general population. Whilst mortality has improved since the condition was first recognized, further evaluation of the patients studied in the cohorts included here is necessary to assess more recent changes in clinical practice.

BackgroundGuidelines recommend Irritable Bowel Syndrome (IBS) diagnosis and management in primary care with minimal investigations; however little evidence exists regarding risk of organic gastrointestinal conditions following diagnosis of IBS and how such risks vary over the long term. This study assesses excess incidence of coeliac disease, inflammatory bowel disease (IBD) and colorectal cancer (CRC) and variation with age and time after IBS diagnosis.MethodsIBS patients and controls were identified within the UK Clinical Practice Research Dataset. Incidence rates were calculated and stratified by age and time since IBS diagnosis with incident rate ratios generated.ResultsFifteen years after IBS diagnosis there is a significant cumulative excess incidence of coeliac disease, IBD and CRC in IBS of 3.7% compared to 1.7% in controls. For every 10000 patient years, IBS patients experienced an additional 4 diagnoses of coeliac disease, 13 of IBD and 4 CRCs. In each condition peak excess incidence was in the 6 months following diagnosis. After one year, increased incidence of coeliac disease remained consistent without variation by age. IBD incidence fell slowly, with higher rates in those under 30. CRC incidence was increased only in patients aged 30 to 74 during the first 5 years.ConclusionSome IBS patients later receive organic gastrointestinal diagnoses, with the early excess incidence likely detected during diagnostic investigation at the time of IBS diagnosis. More than 5 years after IBS diagnosis there is no increased risk of CRC compared to the general population, but a small excess risk of coeliac disease and IBD persists. Overall, though our findings provide reassurance that non-specialists, especially those in primary care, are unlikely to be missing an organic condition in the majority of their patients. This suggests that current guidelines suggesting avoidance of universal referral for these patients are appropriate.