All adult patients with kidney failure referred to a department of renal medicine at one of the four hospitals from the 1st of October 2016 to the 31st of May 2018 were offered the intervention and invited to participate in the study. The inclusion criterion was an estimated glomerular filtration rate below 20 ml/min and based on a clinical judgement made by the contact doctor and/or the contact nurse about the decline in the Estimated glomerular filtration rate to continue. Exclusion criteria were patients who had decided on conservative management, patients with a living donor and a set date for transplantation and patients not able to participate in the intervention due to cognitive impairment. The use of an interpreter was not an exclusion criterion.

The SDM-DC intervention is designed for patients with kidney failure who must make a decision regarding type of dialysis: haemodialysis or peritoneal dialysis. SDM-DC consists of patient and his or her relative(s) being given a patient decision aid called 'Dialysis choice' and booked for meetings with a dialysis coordinator. There were optional videos describing other patients' experiences making this decision. The dialysis coordinators were trained in the why, what and how in relation to SDM-DC and to deliver the intervention by tailoring to patients' needs and using three different communication skills: mirroring, active listening and value clarification.

Shared decision-making questionnaire was used to measure patients' perception of shared decision-making in the clinical encounter. It consists of nine statements to be rated on a six-point scale from 'completely disagree' (0) to 'completely agree' (5) The quality of the decision-making process was calculated as the mean score for each item in the SDM-Q9. To provide a total score of the SDM-Q9 a sum of all items was calculated and standardized on a scale on 0-100.

Decision Quality Measurement was used to measure the quality of the decision. The questionnaire consists of six knowledge statements and six readiness statements. All items on the questionnaire were rated as yes, no or unsure. It also consists of two open questions. A total knowledge and readiness score was calculated and standardized out of 100. Open questions were analysed using descriptive qualitative analysis and reported based on most common to least common comments. We decided that for a home-based treatment and choosing 'Treatment at home' in the preference question or deciding for a hospital-based treatment and not choosing 'Treatment at home' in the preference question were considered as concordant choices. Decision quality was defined as a knowledge score >66% on the knowledge score and combined with the concordance score.