The Swedish Renal Registry: a nationwide registry for chronic kidney disease of all stages

Background National registries which capture patients with chronic kidney disease (CKD) across all stages are scarce. We present here the Swedish Renal Registry (SRR), a nationwide prospective register covering the whole spectrum of CKD. Methods Created in 1991, SRR enrolls CKD patients referred to adult nephrologist care (non-dialysis CKD [ND-CKD], kidney transplantation, maintenance dialysis), with an overall coverage of nearly all nephrology clinics in Sweden. SRR encompasses several interconnected databases in which longitudinal clinical, biological, kidney-related, patient-reported data, as well as provider-level information are collected. This report presents the design of the registry, as well as patients characteristics and temporal trends between 2008 and 2021. Results A total of 45,590 new ND-CKD patients (72 years, 16,656 [36%] women, eGFR 26 mL/min per 1.73m²), and 8829 incident kidney transplant recipients (51 years, 35% women) were enrolled in SRR between 2008-2021. SRR also included 16,034 new patients (68 years, 5420 [34%] women) on maintenance dialysis (70% Hemodialysis [HD], 30% Peritoneal dialysis [PD]). Between 2015 and 2021, 4753 patients (59 years, 1884 [40%] women, eGFR 37 mL/min per 1.73m²) had a registered kidney biopsy. We observed a decrease in HD incidence (69% to 60%, P for trend <0.01) and an increase in PD incidence (26% to 32%, P<0.01) and preemptive transplantation (4.7 to 7.5%, P<0.01). The prevalence of comorbidities is high in all CKD stages and increase as eGFR declines. While nephroangiosclerosis and diabetic kidney disease are the most common etiologies, glomerulonephritis are the most frequent diagnoses in biopsied and transplanted patients. Conclusion The SRR is a nationwide register which aims to contribute to address gaps in our understanding of CKD, to identify important challenges and health priorities, to evaluate real-life clinical management, and to analyze international variations, to improve health outcomes, quality of life, and reduce the burden of CKD.