Govert Veldhuijzen

177 Discussion and future perspectives In chapter 6 we presented the cost effect analysis of implementation of CBE in the endoscopy unit. The strength of this article is the triangular approach that illustrated the effect on costs for endoscopy units, patients and society. While the main readership most probably would be most interested in the effect on costs for the endoscopy unit, the other costs might be more important for your patient and health care policy makers. Another strength was the developed highly detailed cost model including 38 parameters that are affected by CBE implementation. This allows for accurate cost- effect statements. The main limitation of this study was the low response rate (54.5%) of the patient reported data. To be able to evaluate the cost effect for the complete group, we had to extrapolate data, with the risk of assumption bias. Also, other elements of our analysis might have introduced some assumption bias, such as using of average travel distance instead of collecting this data. Strengths of the VR glasses pilot study reported on in chapter 7 were the novel application of this device in endoscopy and the focus on patient acceptance. Important to the design of subsequent trials from the endoscopist perspective is that the use of VR glasses did not interfere with the colonoscopy. The VR glasses study was performed in a real life setting which adds to the external validity of the study. By using Samsung Gear VR to provide distraction, we have chosen a widely available and relatively inexpensive VR device, enhancing the generalizability of the study. This study also comes with limitations. First, the small sample size does not allow robust statements on clinically relevant endpoints like reducing anxiety or pain. As various studies found that visual and/or auditory distraction during endoscopic procedures reduced pain and improved satisfaction we were not able to identify these advantages for VR in this pilot. 9-11 The ideal set-up would be a direct comparison of sedation and analgesics versus VR, instead of VR combined with sedation as done in our pilot. Interestingly, one patient declined the offered sedatives in the VR group (data not shown), maintained excellent comfort 1 and satisfaction scores (9/10). The literature on VR for patients in endoscopy is scarce. A retrospective study of 190 patients found that VR allowed unsedated trans nasal gastroscopy in children and young adults. In this study VR assisted trans nasal gastroscopy was safe and cost-effective for staging of eosinophilic esophagitis. 12 The argument has been made that VR allows avoiding sedation for colonoscopy which fuels patients’ experience. 13 Therefore it is probable that in selected patients VR during colonoscopy will be the preferred option. 14 Strengths of chapter 8 where we report on the validation of the D-GESQ were the strict adherence to WHO guidelines for translating and validating and how we utilized the think-aloud method to ensure face validity. 15 This leads to a tool that has a culturally relevant and comprehensible form while maintaining the intention and meaning of the original questions. 16 9