Inflammatory bowel disease (IBD) is a chronic, relapsing intestinal inflammatory disorder with unidentified causes. Both environmental factors and genetic aspects are believed to be crucial to the pathogenesis of IBD. The incidence and prevalence of IBD have recently been increasing throughout Asia, presumably secondary to environmental changes. This increasing trend in IBD epidemiology necessitates specific health care planning and education in Asia. To this end, we must gain a precise understanding of the distinctive clinical and therapeutic characteristics of Asian patients with IBD. The phenotypes of IBD reportedly differ considerably between Asians and Caucasians. Thus, use of the same management strategies for these different populations may not be appropriate. Moreover, investigation of the Asian-specific clinical aspects of IBD offers the possibility of identifying causative factors in the pathogenesis of IBD in this geographical area. Accordingly, this review summarizes current knowledge of the phenotypic manifestations and management practices of patients with IBD, with a special focus on a comparison of Eastern and Western perspectives.

Although differences in genetic susceptibility and the clinical features of Crohn's disease (CD) have been reported between Asian and Caucasian patients, the disease course and predictors of CD in Asians remains poorly defined. The study therefore aimed to investigate factors predictive of the clinical outcomes of patients with CD in a Korean population.

This retrospective multicenter cohort study included 728 Korean CD patients from 13 university hospitals. The first CD-related surgery or need for immunosuppressive or biological agents were regarded as the clinical outcomes of interest.

A total of 126 (17.3%) CD patients underwent CD-related surgery, while 473 (65.0%) and 196 (26.9%) were prescribed thiopurine drugs and infliximab, respectively. Multivariate Cox regression analysis identified current (hazard ratio [HR] = 1.86; P = 0.018) and former smoking habits (HR = 1.78; P = 0.049), stricturing (HR = 2.24; P < 0.001), and penetrating disease behavior at diagnosis (HR = 3.07; P < 0.001) as independent predictors associated with the first CD-related surgery. With respect to immunosuppressive and biological agents, younger age (< 40 years) (HR = 2.17; P < 0.001 and HR = 2.10; P = 0.006, respectively), ileal involvement (HR = 1.36; P = 0.035 and HR = 2.17; P = 0.006, respectively), and perianal disease (HR = 1.42; P = 0.001 and HR = 1.38; P = 0.038, respectively) at diagnosis were significant predictors for the need of these medications.

In Korean patients with CD, stricturing, penetrating disease behavior, and smoking habits at the time of diagnosis are independent predictors for CD-related surgery. It was also identified that younger age (< 40 years), ileal involvement, and perianal disease at diagnosis are predictive of a need for immunosuppressive or biological agents.

The incidence and prevalence of inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC), are lower in Asia than in the West. However, across Asia the incidence and prevalence of IBD has increased rapidly over the last two to four decades. These changes may relate to increased contact with the West, westernization of diet, increasing antibiotics use, improved hygiene, vaccinations, or changes in the gut microbiota. Genetic factors also differ between Asians and the Caucasians. In Asia, UC is more prevalent than CD, although CD incidence is rapidly increasing in certain areas. There is a male predominance of CD in Asia, but a trend towards equal sex distribution for UC. IBD is diagnosed at a slightly older age than in the West, and there is rarely a second incidence peak as in the West. A positive family history is much less common than in the West, as are extra-intestinal disease manifestations. There are clear ethnic differences in incidence within countries in Asia, and an increased incidence in IBD in migrants from Asia to the West. Research in Asia, an area of rapidly changing IBD epidemiology, may lead to the discovery of critical etiologic factors that lead to the development of IBD.

Inflammatory bowel disease (IBD), common in Melbourne, was rare but is now increasing in incidence in Hong Kong (HK). To investigate whether these are the same diseases in the West and East, potential causes of changing incidence, and to plan resource needs, an appreciation of clinical characteristics in contrasting populations is essential.

Disease characteristics were collected from prospectively populated IBD databases in two specialist centers in Melbourne, Australia and HK.

Of 795 patients (Crohn's disease [CD] : ulcerative colitis [UC] Melbourne 272:159 and HK 161:203), the age of diagnosis was higher, there were proportionally more male patients with CD but no UC sex difference, fewer patients were current or ex-smokers (CD 8% vs 50%; UC 17% vs 35%) and a family history of IBD was less common (2% vs 11%; P < 0.001) in HK compared to Melbourne. Stricturing and perianal CD were more common in HK (12% vs 6%; P < 0.001; and 29% vs 16%; P = 0.001, respectively). In HK for UC, more patients had extensive disease at diagnosis (42% vs 22%) but colectomy was less common (7% vs 20%; P < 0.001). In Melbourne there was greater steroid use at diagnosis and patients were more likely to receive an immunomodulator or anti-tumor necrosis factor agent.

IBD in HK was diagnosed at an older age, and had more complicated disease behavior than in Melbourne. Medical therapy, however, was less intense in HK. These differences may relate to real differences in disease or delayed diagnosis due to late presentation and less disease recognition in HK.

A rising trend in the incidence and prevalence of inflammatory bowel disease (IBD) in Asia has been recognized for the past two decades. It has been postulated that this phenomenon may be related to the westernization of lifestyles, including changes in dietary habits and environmental changes such as improved sanitation and industrialization. Previously we reported that the incidence and prevalence rates of IBD in Asia were low compared with the West, but there was a notably rising secular trend. In this review, we summarize the recent epidemiological data in Asia, characterize the clinical features, risk factors and genetic susceptibility of Asian IBD patients, and compare these to those of Western IBD patients. In the past decade, the incidence and prevalence of IBD reported across Asia, particularly in East Asia, has continued to increase. Familial clustering is generally uncommon in East Asia but appears to be higher in West Asia. The genetic susceptibilities in Asian IBD patients differ from those of White patients, as NOD2/CARD15 mutations are much less common. The clinical phenotypes and complication rates of Asian IBD resemble the White population in general, but with some differences, including lower surgical rates, higher prevalence of males, and higher prevalence of ileocolonic involvement among East Asian Crohn's disease patients, and a low frequency of primary sclerosing cholangitis among IBD patients in East and Southeast Asia.

At the present there are no large-scale epidemiologic data on inflammatory bowel disease (IBD) in the Asia-Pacific region, but several studies have shown an increased incidence and prevalence of IBD in this region. Compared to the West, there appears to exist a time lag phenomenon. With regard to the two main forms of IBD, ulcerative colitis (UC) is more prevalent than Crohn's disease (CD). In addition to geographic differences, ethnic differences have been observed in the multiracial Asian countries. Moreover, the genetic backgrounds are different in the Asian compared to Western patients. For instance, NOD2/CARD15 variants have not been found in Asian CD patients. In general, the clinical course of IBD seems to be less severe in the Asia-Pacific region than in Western countries. Diagnosis of IBD in this region poses special problems. The lack of a gold standard for the diagnosis of IBD, and the existence of a variety of infectious enterocolitis with similar manifestations to those of IBD make the differential diagnosis particularly difficult. So far, Western diagnostic criteria have been introduced for the diagnosis of IBD. A stepwise approach to exclude non-IBD enterocolitis also must be introduced, and a definite diagnosis must include typical histological features. In some patients, follow up and therapeutic trials might be necessary to obtain a definitive diagnosis. A better understanding of the pathogenesis of IBD will allow the development of better diagnostic markers. The management of IBD also poses some special problems in the Asia-Pacific Region. There is often a delay in using proper medications for IBD, and alternative local remedies are still widely used. With a combination of Western guidelines and regional experiences, similar principles can be used for induction and maintenance of remission. A stepwise selection of medications is advocated depending on the extent, activity and severity of the disease. Comprehensive and individualized approaches are suggested for different IBD patients. Deeper understanding of disease pathogenesis and the unique characteristics of IBD in the Asia-Pacific region, combined with reasonable and practical guidelines for drug management and the future use of biological agents would improve the therapeutic outlook of IBD in this region.

Patients frequently ask questions about the lifetime prognosis of Crohn's disease. The aim of this study was to describe the outcomes of Crohn's disease more than 20 years after diagnosis.

Data from all patients with Crohn's disease whose diagnosis had been performed before 1st January 1978 were analyzed. All referred patients filled in a medical and health-related quality-of-life questionnaire.

Among 273 patients with Crohn's disease diagnosed more than 20 years ago, 141 (52%) patients answered our questionnaire, 45 (16%) patients were alive but did not wish to answer our questionnaire, 51 (19%) could not be traced and 36 (13%) died before July 1998. At the end of follow-up, 25.7 (20.0-59.3) years after diagnosis, 24% had a relapse in the previous 12 months, and 48% and 28% had quiescent disease with and without treatment, respectively. These ratios were not different from those observed three years after Crohn's disease diagnosis. Sixteen patients died within 20 years after CD diagnosis, including 11 from CD-related causes. The risk of death estimated by Kaplan-Meier life-tables analysis was non-significantly higher if death was related to CD. An ileal or colic adenocarcinoma was noted in 6 (3.4%) patients.

Crohn's disease activity does not burn out with time, and roughly one-quarter of the patients had active disease 20 years after diagnosis.

Studies of Asians in Asia show relatively low incidence rates for ulcerative colitis and Crohn's disease compared with North America and Europe. The prevalence of ulcerative colitis in migrant South Asians in Europe is similar to Europeans, whereas the prevalence of Crohn's disease for migrant South Asians in Europe is decreased compared with Europeans. The prevalence for both ulcerative colitis and Crohn's disease in Japan and Korea is relatively low. There are no obvious differences in age or sex distribution or rates of familial aggregation, and there are no significant differences in the clinical characteristics and natural history of ulcerative colitis and Crohn's disease in Asians compared with other racial groups with inflammatory bowel disease.