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Does VSL#3 Really Improve Symptoms in Children With IBS?

Shulman, Robert J.; Smith, E. O’Brian

Journal of Pediatric Gastroenterology and Nutrition: January 2012 - Volume 54 - Issue 1 - p 109
doi: 10.1097/MPG.0b013e31823df69b
Letters to the Editor

Baylor College of Medicine, Houston, TX

To the Editor: We read with great interest the report by Guandalini et al (1) on the effectiveness of the probiotic VSL#3 in improving symptoms in children with irritable bowel syndrome (IBS). A number of issues, however, impair interpretation of the results. The crossover design of the study is extremely problematic. A number of studies evaluating probiotics have shown that their beneficial effects on IBS symptoms extend weeks beyond the treatment period (2–5). In patients with ulcerative colitis, VSL#3 exerts a significant effect on stool pH at least 15 days after administration ceases, a time when the organisms are no longer recoverable in feces based on studies in patients with IBS, even with using older methodology (6,7). Thus, there likely was a carryover effect between the 2 study periods, clouding interpretation of the results. Indeed, this is one of the reasons that an expert panel does not recommend the use of crossover trials for IBS (8). Additional causes of concern include lack of a CONSORT flow diagram, lack of intention-to-treat data analysis, and failure to use a 2-way analysis of variance (to account for group).

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