A Mobile Application to Improve the Quality of Colonoscopy in Colorectal Cancer Screening Program (PrepColon APP)

STUDY DESIGN AND METHODS Study Design: Phase 1: Design of the mobile application (APP): The APP will be designed in a participatory manner by the research team of the project, formed by doctors, nurses, statisticians and telecommunications engineers. The application should be usable with both Android and iOS devices, so we will use the Flutter framework to build apps for different platforms with a single code base. When arranging a colonoscopy, the patient will install the APP on their mobile phone and indicate the date and time of the test. The APP will be responsible for supporting the preparation of the colon cleansing, for which, in addition to being able to visualize the corresponding information, it will make use of notifications to show diet reminders and laxative intakes. More specifically, these could be some notifications: * (3 days before the appointment) - Notification of start of preparation with a low fibre diet * (24 hours before the appointment) - Notification of .laxative intake.. The APP will also consider the comorbidities and drugs of each participant. It can be adapted to the different types of laxative (4, 2 or 1 litre) and notify the need to discontinue anticoagulant and/or antiplatelet treatments by contacting with the primary care physician. Additionally, the application may ask short questions to control the laxative intake instruction. The user must confirm the appointment 48 hours in advance. The design of the APP aims to be intuitive and easy to use by the target population (50-69 years), allowing to adapt the font size and zoom in on the images to facilitate the visualization of the information. The APP will be multilingual for English and Spanish, and others may be incorporated if deemed necessary. An agile and iterative methodology of software development will be followed as SCRUM in the realization of the APP. Thus, sprints of about 3 weeks will be planned with delivery of functional software that will progressively incorporate the different functionalities planned for the APP. Phase 2: Re-evaluation of the APP after the inclusion of 30 patients, the APP will be re-evaluated through a usability questionnaire and adjustments and changes will be made if necessary Phase 3: Prospective, multicentre and randomized study in asymptomatic patients between 50 and 69 years who attend screening colonoscopy after a positive FIT \>100 ng / ml) The study will be carried out in the Digestive Service of 3 hospitals in Castilla y León: Virgen de la Concha Hospital in Zamora, Medina del Campo Hospital and Río Hortega University Hospital in Valladolid. Participants will be randomized into two groups according to the instructions given to perform the preparation of the colon prior to colonoscopy: group A: perform the preparation with the written instructions delivered in the consultation and group B: the investigators will give the instructions in writing and will also indicate how to install the APP to the participants.