Background and Aims
Chronic kidney disease (CKD) is a common disease with a heterogeneous course. The Kidney Failure Risk Equation (KFRE) is designed to predict 5-year End stage renal disease (ESRD). This score has shown poor performance in predicting 5-years ESRD in elderly patients, probably because of a competitive risk with death. Indeed, patients with type 2 diabetes are numerous and older than non-diabetic patients, with higher risks of death, and thus à higher competitive risk. In this context, we aimed to evaluate the performance of the KFRE score at 5 years, in a cohort from a tertiary center, according to diabetic status.
Method
The CKD Caremeau (CKDC) cohort is a single-center tertiary cohort of adults seen by a nephrologist for CKD. We studied CKDC patients included between January 2008 and December 2017 and followed them. We excluded patients younger than 45 years. KFRE score covariates were collected at the first visit, and Renal replacement therapy (RRT) (dialysis or kidney transplantation) and death before ESRD were collected during follow-up through December 2022. Multiple imputation (Monte Carlo) was used for missing albuminuria. Score performance was calculated with discrimination (area under curve (AUC)) and calibration (observed versus predicted risks), according to diabetic status, at 5 years.
Results
Of the 3046 patients included, 1288 (42%) had diabetes. 558 (18%) albuminuria were missing and imputed. For diabetic patients, median follow-up time was 5.3 [3.0–7.6] years, median age was 73 [66–80] years, 843 (65%) patients were males, median eGFR was 38 [27–50], median albuminuria was 204 [57–671] mg/g, 177 (14%) developed ESRD, and 398 (30%) died, with a median 5-years KFRE score of 4 [0.65–17.6] %. For non-diabetic patients, median time of follow-up was 5.5 [3.3–8.2] years, median age was 72 [63–81] years old, 1027 (58%) were males, median eGFR was 40 [27–53], median albuminuria was 113 [38–399] mg/g, 205 (12%) experimented ESRD, and 501 (29%) died, with a median 5-year KFRE score of 2 [0.18–14] %. Discrimination was not modified by diabetic status at 5 years (p = 0.67). Calibration was also unaffected by diabetic status, with an overall overestimation at 5 years.
Conclusion
The performance of the KFRE score was not modified by diabetic status, meaning that age is probably more important than diabetic status for the competitive risk of death in CKD patients.
