Clinical impact of the Kidney Failure Risk Equation for vascular access planning

ABSTRACT Background Risk-based thresholds for arteriovenous (AV) access creation has been proposed to aid vascular access planning. We aimed to assess the clinical impact of implementing the Kidney Failure Risk Equation (KFRE) for vascular access referral. Methods A total of 16 102 nephrology-referred chronic kidney disease (CKD) patients from the Swedish Renal Registry 2008–18 were included. The KFRE was calculated repeatedly, and the timing was identified for when the KFRE risk exceeded several pre-defined thresholds and/or the estimated glomerular filtration rate was 15 mL/min/1. 73 m2 (eGFR15). To assess the utility of the KFRE/eGFR thresholds, cumulative incidence curves of kidney replacement therapy (KRT) or death, and decision-curve analyses were computed at 6 and 12 months, and 2 years. The potential impact of using the different thresholds was illustrated by an example from the Swedish access registry. Results The 12-month specificity for KRT initiation was highest for KFRE 50% 94. 5 95% confidence interval (CI) 94. 3–94. 7 followed by KFRE 40% 90. 0 (95% CI 89. 7–90. 3), while sensitivity was highest for KFRE 30% 79. 3 (95% CI 78. 2–80. 3) and eGFR 15 mL/min/1. 73 m2 81. 2 (95% CI 80. 2–82. 2). The 2-year positive predictive value was 71. 5 (95% CI 70. 2–72. 8), 61. 7 (95% CI 60. 4–63. 0) and 47. 2 (95% CI 46. 1–48. 3) for KFRE 50%, KFRE 40% and eGFR 15, respectively. Decision curve analyses suggested the largest net benefit for KFRE 40% over 2 years and KFRE 50% over 12 months when it is important to avoid the harm of possibly unnecessary surgery. In Sweden, 54% of nephrology-referred patients started hemodialysis in a central venous catheter (CVC), of whom only 5% had AV access surgery 6 months before initiation. Sixty percent of the CVC patients exceeded KFRE 40% a median of 0. 8 years (interquartile range 0. 4–1. 5) before KRT initiation. Conclusions The utility of using KFRE 40% and KFRE 50% is higher compared with the more traditionally used eGFR threshold 15 mL/min/1. 73 m2 for vascular access planning.