Role of the gut microbiome in mediating lactose intolerance symptoms

example, in a highly cited large multicentre study (n=2600 patients), the CTC sensitivity for detection of ≥10 mm colonic polyp was found to be 90%. Another example is a pooled analysis (n=5328 patients) used recently by the US Preventive Service Task Force concluding that the CTC sensitivities to detect 6 mm and 10 mm colonic polyps were 86% and 89%, respectively, which are significantly higher than the results reported by Cash et al. Despite such disparate findings, there is no attempt to explain the differing results of this trial compared with prior larger validated trials. ► The manuscript states that ‘All CCE videos and CTC images were evaluated by one of two expert central readers who documented study quality as well as location and size of any colorectal polyps or masses’. It would be helpful to readers to understand the definition of ‘expert readers’ in terms of the number of CTC previously interpreted, degree of formal training and/or years of experience, especially in light of the surprisingly lower sensitivities of CTC described. ► Another missing component of this paper is the description of study limitations, even potential ones, which are an essential component of scientific discussion. ► The following are the striking differences between CCE and CTC: – Difference in examination duration: the median time needed for CCE was about 5 hours versus usually less than 1 hour for CTC. – Difference in intensity of bowel cleansing regimen: more intense bowel prep and cathartic boosters are needed for CCE. 6 – Difference in study completion rate: four patients assigned to CCE while one patient assigned to CTC had incomplete examination (the rate of incomplete examination is four times higher in the CCE arm compared with the CTC arm). Although these differences may not be directly related to diagnostic accuracy, a full discussion of both the advantages and the limitations of each screening modality would be helpful to readers when applying the results of any study to an individual patient’s circumstances. ► The wide exclusion criteria specific to the use of CCE (excluding patients with dysphagia, swallowing disorder, gastroparesis, bowel dysmotility, bowel stricture or fistula, patients with cardiac pacemaker or renal impairment) may limit the generalisability of the study findings. We thank you and the readers for the time and attention to our concerns. We believe that more studies are needed to reach a conclusive recommendation.