Abstract Body (Do not enter title and authors here): Background
The Kidney Failure Risk Equation (KFRE) is an established calculator to predict the risk of kidney failure among patients with chronic kidney disease (CKD). Patients with CKD are more likely to die from cardiovascular (CV) causes than from renal causes, and more likely to experience a non-fatal CV event than to progress to kidney failure. The CV predictive ability of the KFRE among patients with CKD is unclear.

Methods
We investigated the association of the 8-variable (age, sex, urine albumin-creatinine ratio [UACR], estimated glomerular filtration rate [eGFR], serum albumin, serum phosphate, serum bicarbonate, serum calcium) 5-year KFRE with CV disease (CVD) and death among 3,034 patients with CKD (eGFR 15-60 mL/min/1.73m²) in the Chronic Renal Insufficiency Cohort (CRIC). KFRE was modeled continuously and by quartiles. CVD was defined as the composite of heart failure hospitalization, myocardial infarction, or stroke. All-cause mortality was a key secondary endpoint.

Results
Mean eGFR was 39 ±11 mL/min/1.73m²; median UACR was 89 mg/g [25-75th percentile 13, 619]. Median KFRE 5-year score was 0.7% [25-75th percentile 0.2, 2.9]. Five-year event rates for the primary endpoint for the lowest to highest quartiles of KFRE were 11.6%, 17.7%, 25%, and 31% (P<0.001). KFRE score (per 1-unit higher log-transformed KFRE score) was associated with a 27% higher risk of CVD (HR 1.27; 95%CI 1.22, 1.33), and a 24% higher risk of death (HR 1.24; 95%CI 1.19, 1.30). When analyzed by quartiles, higher KFRE was associated with more than a 3-fold higher risk of CVD (HR Q4:Q1 3.31; 95%CI 2.67, 4.10), and more than a 3-fold higher risk of death (HR Q4:Q1 3.28; 95%CI 2.62, 4.11).

Conclusions
Among participants of CRIC, a higher KFRE was associated with a higher risk of CVD and all-cause death. As patients with CKD are at higher risk of both adverse kidney and CV outcomes, this suggests that KFRE could be used as a broad and simple risk-stratification tool for patients with CKD.