This is an ERASMUS + project funded by the European Union (number 2020–1-ES01-KA2014-083141, http://goodrenal.eu/) named GoodRENal that aims to develop educational material for patients on HD, their carers and health care professionals working in the dialysis clinics of four countries: 1. Renal Unit of AHEPA Hospital, Thessaloniki, Greece; 2. Hospital de Manises, Nephrology Service, Manises, Spain; 3. Skåne University Hospital, Department of Nephrology, Lund, Sweden and, 4. University Hospitals Leuven, Department of Nephrology, Leuven, Belgium. As part of this project, educational material was developed based on issues raised by the patients, health care professionals and carers in exploratory questionnaires previously administered based on what they perceived as their main needs, barriers and facilitators to enable adherence to dietary recommendations, increase physical activity and improve emotional well-being [10]. The educational material was developed by a group of clinicians comprising 3 nephrologists, 3 physiotherapists, 2 psychologists and one dietitian. The physiotherapists and the dietitian are trained professionals that work with specificities inherent to CKD and dialysis treatment. The material was developed aiming to discuss five main drivers using the following questions: Why is it important?, Who are the candidates?, When and where?, What and how?, and Which are the alarm signals?. This educational material aimed to provide content for the peer-to-peer-training of health care professionals from the participating dialysis units about specific aspects related to physical activity, adherence to nutrition recommendations, cognitive state and psychological well-being of patients on chronic HD. All health care professionals working in the dialysis unit were invited to participate in the peer-to-peer sessions. The group that participated in the training sessions varied from one center to another, but in general included the nephrologists, nurses, dietitians and physiotherapists. The educational material comprised three brochures, one for Nutrition, a second for physical activity, and a third for psychological and cognitive well-being. Training took place between March and October, 2022 at the dialysis clinics of each participating center, as shown in Table 1. It was adapted according to staff availability and to the room in which the training was carried out. As most HD units suffer from a shortage of staff and staff with busy schedules, a novel methodology was developed consisting of micro-sessions of training. These micro-sessions took place at a work station during their regular activities within the HD unit. The sessions were led either by a physiotherapist or by a nurse responsible for educating staff on the basis of the availability of each HD unit. The material in the brochures was developed in English and then translated to Greek, Spanish, Swedish and Dutch by native speakers from each country. This translated material can be found at the GoodRENal webpage (https://goodrenal.es/results-3/). From 1 to 30 days after the end of training, the participants were asked to anonymously respond to an electronic survey on the User Satisfaction Evaluation Questionnaire with 10 statements about their opinion on the peer-to-peer training. The answers for the statements were rated from 1 to 5 as very satisfied, satisfied, neutral, unsatisfied, and very unsatisfied, respectively, and from statements 6 to 10 as strongly agree, agree, neutral, disagree, and strongly disagree, respectively. This study complies with the criteria of the Declaration of Helsinki. The ethics committees from the entities involved approved the study. Since the current study has no intervention nor processing of personal data in the electronic questionnaire, there was no need for the participants to sign an informed consent form prior to their participation in the study.