There has been major progress in our understanding of the irritable bowel syndrome (IBS), and novel treatment classes have emerged. The Rome IV guidelines were published in 2016 and together with the growing body of Asian data on IBS, we felt it is timely to update the Asian IBS Consensus. Key opinion leaders from Asian countries were organized into 4 teams to review 4 themes: symptoms and epidemiology, pathophysiology, diagnosis and investigations, and lifestyle modifications and treatments. The consensus development process was carried out by using a modified Delphi method. Thirty-seven statements were developed. Asian data substantiate the current global viewpoint that IBS is a disorder of gut-brain interaction. Socio-cultural and environmental factors in Asia appear to influence the greater overlap between IBS and upper gastrointestinal symptoms. New classes of treatments comprising low fermentable oligo-, di-, monosacharides, and polyols diet, probiotics, non-absorbable antibiotics, and secretagogues have good evidence base for their efficacy. Our consensus is that all patients with functional gastrointestinal disorders should be evaluated comprehensively with a view to holistic management. Physicians should be encouraged to take a positive attitude to the treatment outcomes for IBS patients.

Objective Limitations of existing impedance-pH thresholds include small sample size of normative studies, inclusion of artefactual pH drops and incorrect identification of impedance reflux events. We aimed to obtain new impedance-pH thresholds from expert consensus analysis of tracings from a large number of healthy subjects. Design Of 541 studies performed worldwide using two different systems (Diversatek, USA, and Laborie, Netherlands), 150 tracings with oesophageal diagnoses, behavioural disorders and study-related artefacts were excluded. The remainder studies were subject to two reviewer consensus analysis, in-person or through video conference, consisting of editing meals and pH drops, identification of impedance reflux and postreflux swallow-induced peristaltic wave (PSPW) using strict pre-established criteria and measurement of distal mean nocturnal baseline impedance (MNBI). Results Consensus analysis was performed in 391 tracings (age 32.7 years, range 18–71, 54.2% female). Normative thresholds were significantly different between Diversatek and Laborie (total acid exposure time: 2.8% and 5%; reflux episodes: 55 and 78; MNBI at 3 cm: 1400 and 1500 ohms, at 5 cm: 1400 and 1800 ohms). Males had higher acid exposure, more reflux episodes and lower MNBI. Significant regional differences were identified, including higher PSPW scores in Western countries, and higher MNBI in Asia using Diversatek, and higher acid exposure in the Netherlands, higher MNBI in Asia and South Africa, and lower MNBI in Turkey using Laborie. Conclusion Normal impedance-pH monitoring thresholds have regional and system-related differences. Clinical interpretation needs to use normal thresholds valid for the system used and world region, following careful editing of the tracings.

Pataramon Vasavid, Tawatchai Chaiwatanarat, Pawana Pusuwan, Chanika Sritara, Krisana Roysri, Sirianong Namwongprom, Pichit Kuanrakcharoen, Teerapon Premprabha, Kitti Chunlertrith, Satawat Thongsawat, Siam Sirinthornpunya, Bancha Ovartlarnporn, Udom Kachintorn, Somchai Leelakusolvong, Chomsri Kositchaiwat, Suriya Chakkaphak, and Sutep Gonlachanvit. J Neurogastroenterol Motil 2014;20:371-8. http://dx.doi.org/10.5056/jnm13114

Gonlachanvit S. J Neurogastroenterol Motil. 2010 Apr;16(2):131-138. http://dx.doi.org/10.5056/jnm.2010.16.2.131

Aim The Rome II and III diagnostic criteria for dyssynergic defecation require the exclusion of irritable bowel syndrome (IBS). To prospectively study whether the presence of IBS affects the outcome of biofeedback therapy in dyssynergic defecation patients. Methods Consecutive patients with dyssynergic defecation underwent biofeedback therapy. Dyssynergic defecation was diagnosed based on symptoms, anorectal manometries, balloon expulsion tests, and colonic transit studies. The defecation dynamics and balloon expulsion time were evaluated at the end of the biofeedback therapy in all patients. IBS symptoms were graded before and 4 weeks after the biofeedback therapy using a 4-point Likert scale. Failure of the biofeedback therapy was defined as <50% improvement of constipation symptoms, which were evaluated using a 10 cm long visual analog scale before and 4 weeks after biofeedback therapy. Results Fifty patients completed the study. The biofeedback therapy was successful in 30 patients. Twenty-nine patients fulfilled the Rome II criteria for IBS. Patients with or without IBS demonstrated similar responses to the biofeedback therapy (16 of 29 vs. 14 of 21, P>0.05). The disappearance of IBS symptoms was observed more frequently in patients with an improved defecation index compared with those with no improvement (8 of 12 vs 4 of 17, P<0.05). A high pretreatment constipation symptom score, a high rectal sensory threshold, and a delayed colonic transit time were associated with a poor treatment outcome. Conclusions The presence of IBS in dyssynergic defecation did not affect the outcome of biofeedback therapy. In addition, treating dyssynergic defecation patients with IBS by biofeedback therapy improved both constipation and IBS symptoms.

A low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet has been recommended for irritable bowel syndrome (IBS) patients. This study compared the efficacy of two types of dietary advice: (1) brief advice on a commonly recommended diet (BRD), and (2) structural individual low-FODMAP dietary advice (SILFD). Patients with moderate-to-severe IBS were randomized to BRD or SILFD groups. Gastrointestinal symptoms, 7-day food diaries, and post-prandial breath samples were evaluated. The SILFD included (1) identifying high-FODMAP items from the diary, (2) replacing high-FODMAP items with low-FODMAP ones by choosing from the provided menu. The BRD included reducing traditionally recognized foods that cause bloating/abdominal pain and avoidance of large meals. Responders were defined as those experiencing a ≥30% decrease in the average of daily worst abdominal pain/discomfort after 4 weeks. Sixty-two patients (47 F, age 51 ± 14 years), BRD (n = 32) or SILFD (n = 30), completed the studies. Eighteen (60%) patients in SILFD vs. 9 (28%) in the BRD group fulfilled responder criteria (p = 0.001). Global IBS symptom severity significantly improved and the number of high-FODMAP items consumed was significantly decreased after SILFD compared to BRD. Post-prandial hydrogen (H₂) breath production after SILFD was significantly lower than was seen after BRD (p < 0.001). SILFD was more effective than BRD. This advice method significantly reduced FODMAP intake, improved IBS symptoms, and lowered intestinal H₂ production.