Performance of the Kidney Failure Risk Equation according to diabetic status in the CKD-CAREMEAU cohort of patients with chronic kidney disease.

Background: The Kidney Failure Risk Equation (KFRE) estimates the risk of kidney replacement therapy (KRT) at 5 years. Patients with diabetes mellitus are at high risk of KRT and death, a competing event. This study assesses the performance of the 5-year KFRE in patients with diabetes mellitus, compared to non-diabetic patients and considering age, in a cohort of patients evaluated by a nephrologist at a tertiary care center.

Methods: The CKD-CAREMEAU cohort included all patients who visited a nephrologist for chronic kidney disease (CKD) before KRT between 2008 and 2017. The 5-year KFRE was calculated for each patient, based on their baseline characteristics. The study evaluated performance regarding discrimination and calibration, taking the patient's diabetic status and age into account.

Results: The study included 2935 patients with a median age of 73 [65-80] years, 1800 of whom were men (61%), and 1249 (43%) who were affected by diabetes. The incidence of KRT was higher in diabetic patients (167 (13%)) than in non-diabetic patients (184 (11%))(p = 0.04). Additionally, the death rate within five years after inclusion was not statistically higher for diabetic patients (351 (28%)) than non-diabetic patients (443 (26%))(p = 0.3). Diabetic status affected neither discrimination nor calibration. However, the equation overestimated the risk for higher-risk patients, especially among the elderly.

Conclusions: Our study found no difference in the 5-year KFRE performance between diabetic and non-diabetic patients. However, performance was worse for patients over 75 years old.