Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Fürst, S.
Predictive factors for a response to rifaximin in patients with irritable bowel syndrome
Humanmedizin; [ Diplomarbeit ] Graz Medical University; 2017. pp.
[OPEN ACCESS]
FullText
- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Constantini-Kump Patrizia
- Hoegenauer Christoph
- Rainer Florian
- Altmetrics:
- Abstract:
- Introduction: Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder. The pathophysiology of the disease is insufficiently explored but alterations of intestinal microbiota including small intestinal bacterial overgrowth (SIBO) are thought to play a role in the development of IBS. SIBO can be diagnosed by lactulose breath test and treated with rifaximin, but studies investigating the efficacy of the non-absorbable antibiotic are controversial, as only a subset of IBS patients with SIBO and also SIBO-negative patients seem to benefit. Moreover, increased intestinal permeability indicated by elevated serum zonulin levels has been found in diarrhea-dominant IBS patients (IBS-D) but not in constipation-dominant IBS patients (IBS-C). Therefore, we investigated the predictive value of lactulose breath test for a response to rifaximin in IBS patients. Furthermore, we measured serum zonulin levels in our patients to find associations with IBS subtypes, symptom severity and alterations of lactulose breath test. Material and Methods: IBS-D (n=11) and IBS-C (n=8) patients were included. Lactulose breath test (25 g lactulose), measuring both hydrogen and methane every 30 min for 3 h, was performed before and after 10-day rifaximin intake (1200mg/daily) Symptom severity was assessed by a validated questionnaire, the IBS severity scoring system (IBS-SSS). Serum zonulin concentrations were measured before as well as after antibiotic treatment. Results: Overall, 44% of IBS patients symptomatically improved after rifaximin intake. This improvement was mainly seen in IBS-D patients, who improved significantly (p=0.003), whereas IBS-C patients remained unchanged. IBS-D patients showed a trend for having lower, but not significant, hydrogen values compared to IBS-C patients. Patients with 90 min hydrogen increase < 20 ppm improved significantly (p=0.028), but no significant difference was observed when analyzing absolute hydrogen values between patients with and without improvement. IBS-D patients had significantly higher (p=0.009) serum zonulin values compared to IBS-C patients. Serum zonulin was not associated with symptom severity. Patients with IBS-C and low zonulin levels showed significantly higher (p=0.037) total 3 h H2 excretion. Further, serum zonulin of patients who improved decreased significantly (p=0.046) after rifaximin. Conclusion: In summary, IBS-D patients improved after a therapy with rifaximin. Even though low hydrogen levels in expiratory air seem to identify patients who will benefit from a therapy with rifaximin, the lactulose breath test did not reveal significant predictive values. We could confirm abnormal high serum zonulin levels in IBS-D patients. Symptom improvement could be associated with an improvement of intestinal permeability indicated by a decrease of serum zonulin. The positive effect of rifaximin in IBS-D patients may be due to its impact on altered microbiota composition, which is not detectable by lactulose breath test.