Comparing CKD populations with T1D and T2D: a perspective based on the FINE-ONE and FIDELITY populations.

Chronic kidney disease (CKD) is a common comorbidity of both type 1 diabetes (T1D) and type 2 diabetes (T2D) and is associated with increased mortality, end-stage kidney disease and cardiovascular disease risk. Despite standard-of-care treatment with renin-angiotensin system inhibitors added to blood pressure and glycaemic control, people with CKD and T1D have a residual risk of CKD progression. Advances in therapeutic management have been limited over the past 3 decades, especially compared with CKD in T2D, for which new treatment options have emerged in the last 5 years. In this review article we discuss the similarities and differences between T1D and T2D populations with CKD, including epidemiology, pathophysiology and clinical findings. Additionally, we explore the use of albuminuria as a potential bridging biomarker to extrapolate clinical evidence from one population to the other. This concept could offer a promising strategy to narrow the gap in treatment availability between these populations and address the unmet therapeutic need in people with CKD and T1D. The FINE-ONE trial is investigating the non-steroidal mineralocorticoid receptor antagonist finerenone in a population with CKD and T1D using the change in urine albumin:creatinine ratio from baseline over 6 months as its primary endpoint and bridging biomarker. Similarities between the populations from FINE-ONE trial and FIDELITY (a pooled dataset of individuals with CKD and T2D included in two large phase 3 clinical trials of finerenone) may inform the translation of clinical evidence on finerenone from people with CKD and T2D to those with CKD and T1D.