Targeting Chemoprophylaxis in Venous Thromboembolism Using Biomarker Guidance

Abstract

ment, but we chose the equivalence design initially to determine the similarity of laparoscopic sleeve gastrectomy to laparoscopic Roux-en-Y-gastric bypass also allowing the potential treatment effect difference in either direction from the reference treatment of laparoscopic Roux-en-Y-gastric bypass. 4 Defining either the noninferiority margin or the equivalence margins to assess the meaningful clinical difference is always challenging. Sometimes these margins have to be set somewhat arbitrarily especially when very little data are in the literature at the time of the trial planning.Both Martin and colleagues as well as Zhang and Ge highlight the importance of understanding randomized clinical trial designs regarding the primary end point choice and assessment of the secondary outcomes. Martin and colleagues also suggest to consider Barrett esophagus as a primary outcome for future trials. At 10 years, the prevalence of Barrett esophagus in our trial was very low (4%) with no difference between laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y-gastric bypass. 1 To demonstrate any difference between the procedures in such a rare event as Barrett esophagus, the number of enrolled patients would need to be very extensive and in real life, such a trial would not be feasible. For the secondary end point assessment, Zhang and Ge raise the important point of anemia at long-term follow-up. We have collected these data, but these micronutrient deficiencies fell outside the already wide scope of this 10-year report. These data will be reported separately, but as a secondary end point, the trial is naturally underpowered for this comparison.We fully agree with both author groups on the importance of preoperative GERD assessment. However, Barrett esophagus is not the main issue as the prevalence seems to be much lower 1,5 than previously reported, 6 but GERD symptoms and esophagitis do play a major role. We need more research on optimal assessment uniformly standardized preoperative GERD symptoms and endoscopic findings and their association with long-term outcomes as a part of a multifactorial evaluation to enable optimal procedure tailoring.