Govert Veldhuijzen

162 Chapter 8 reduced. But although the most cost effective option, e-mail does not yield the best response rate, in comparison with mail or telephone. 33 The response rate would have been higher when a patient filled out the questionnaire on the hospital bed, chosen to do in both the K-GESQ and R-GESQ studies. Benzodiazepines however causes an euphoric state on the day after endoscopy, which could lead to overestimation of satisfaction. 32 . Another limitation is recall bias when patients complete the questionnaire after 30 days. Unfortunately, the appropriate timing for questionnaires after endoscopy has not been determined. 34 In our opinion, some recall bias is acceptable as the chosen timing gives a better reliability compared to completing the questionnaire under sedation. We decided that by sending the e-mail 30 days after endoscopy, a homogenous response time was achieved. Reminding e-mails were not sent out, because that could have affected the homogeneity of the response time. The wide variation in response time in the original study might well have affected the results. 26 In conclusion , our study describes the validation process of the GESQ in Dutch. The D-GESQ was found to have high internal and construct validity. We recommend the D-GESQ for routine use in daily clinical practice to continuously improve the quality of patient care in the endoscopy unit. ACKNOWLEDGMENTS The D-GESQ trial is an investigator-initiated trial. Authors’ contributions MdJ carries out the trial. MdJ and GV conceived the study, organized the design and coordination of the study and drafted the first version of this manuscript. AvE and CR participated in the design and coordination of this study. PS supervised the final manuscript. All authors read and approved the final manuscript. Authors’ information The authors declare that they have no competing interests Acknowledgements The authors would like to thank Wietske Kievit and Reinier Akkermans for their statistical knowledge and support. This trial was funded by the Radboud university. Medify (software developer) had no role in the design and conduct of the study or in the writing and submission of the manuscript.