The Non-Dialysis Chronic Renal Insufficiency study (ND-CRIS): an open prospective hospital-based cohort study in France

Background: Chronic kidney disease (CKD) amounts to a heavy burden for health services. There is no long-running epidemiological tool for CKD before dialysis. We here present the protocol for a cohort of patients with ``non-dialysis'' CKD receiving care in the Bourgogne-Franche-Comte region of France. The aim of this cohort was to periodically describe the characteristics of patients included and their care provision, to analyse evolution in care and patients' kidney function outcomes. Methods: The ND-CRIS cohort is prevalent and incident. Patients are included in the cohort if over 18, with a glomerula filtration rate (GFR) <60 ml/min/1.73 m2, non-dialysed, informed on the research and not having opposed it, and followed by a nephrologist in one of the 9 centres in the region, (3 pilot centres joined by 6 others in 2015). All the patients are followed up, with varying time lapses according to the degree of GFR deterioration. Data is collected by clinical research assistants (CRAs) using a dedicated computerised case-report form (CRF). Professional practices are assessed using indicators defined by the French Health Authority. The follow-up of patients included should enable assessment of the evolution of their GFR and co-morbidities. The periodic descriptions should give insight into evolution in epidemiological terms. Discussion: The ND-CRIS meets a need in epidemiological tools in France for CKD. The cohort does claim to be representative, of ND-CKD patients receiving care from nephrologists. The open and incident nature of the cohort and the number of patients included in the ND-CRIS should provide answers to questions that cannot be answered by smaller solely prevalent cohorts. The numbers of patients included over the study period (2391 patients in 3 centres in 3 years) suggests that the figure of 5000 patients should be reached by 2017. The participation of nephrologists and the rate of inclusions point to the feasibility of the implementation of this cohort. Beyond the information to be found in the CRFs, this cohort should also enable ad hoc studies, in particular in the area of pharmaco-epidemiology, and it could later serve as a research platform and as a public health surveillance tool.