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

Ulrika Hahn Lundström; Chava L Ramspek; Friedo W Dekker; Merel van Diepen; Juan Jesus Carrero; Ulf Hedin; Marie Evans

doi:10.1093/ndt/gfae064

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

Nephrol Dial Transplant. 2024 Mar 14:gfae064. doi: 10.1093/ndt/gfae064. Online ahead of print.

Authors

Ulrika Hahn Lundström¹, Chava L Ramspek², Friedo W Dekker², Merel van Diepen², Juan Jesus Carrero³, Ulf Hedin⁴, Marie Evans¹

Affiliations

¹ Division of Renal medicine, CLINTEC, Karolinska Institutet, Stockholm, Sweden.
² Dep of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
³ Dep of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
⁴ Dep of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.

PMID: 38486367
DOI: 10.1093/ndt/gfae064

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: 16,102 nephrology-referred chronic kidney disease (CKD) patients from the Swedish Renal Registry 2008-2018 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 <15 ml/min/1.73m2 (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, 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/1.73m2 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 two 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 which only 5% had AV access surgery >6 months before initiation. 60% 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 to the more traditionally used eGFR threshold <15 ml/min/1.73m2 for vascular access planning.

Keywords: CKD; arteriovenous fistula; catheter; epidemiology; haemodialysis; vascular access.