#2958 Can the Kidney Failure Risk Equation (KFRE) be used in ANCA associated glomerulonephritis?
Authors: Moore Louise R , Eihebholo Angela , Floyd Lauren , Morris Adam , Dhaygude Ajay , Elsayed Mohamed 
Published: May 2024

Background and Aims

The Kidney Failure Risk Equation (KFRE) provides a 2 and 5 year probability of treated kidney failure for a patient with chronic kidney disease (CKD) stage 3a to 5. KFRE has been validated in over 30 countries, including the United Kingdom (UK) and has become a useful tool to aid clinical decision making [1]. However there has been limited validation to determine if KFRE can be used in primary renal pathologies such as ANCA associated glomerulonephritis (AAGN).

We conducted a retrospective cohort study of patients with AAGN at a single centre in Lancashire, UK to determine if KFRE accurately predicts end stage kidney disease (ESKD).

Method

Patients diagnosed with AAGN between 2009 and 2018 were screened for inclusion. Exclusion criteria included mortality within 6 months of diagnosis, those that remained dialysis dependent 6 months after diagnosis, transfer out of area, eGFR &gt;60 ml/min/1.73 m2 and missing biochemical results required to calculate KFRE. Baseline and clinical characteristics were collected. The UK 4-variable KFRE was calculated at 6 months (±3 months) and 18 months (±3 months) after initial diagnosis of AAGN (1). Clinical outcomes including ESKD (dialysis or transplantation) were recorded.

Statistical analysis was performed. The median and interquartile range were used for continuous variables and frequency and percentage for absolute values. The median and interquartile range were calculated for KFRE. The area under the received operator characteristic curve (AUC) was used to calculate discrimination of KFRE.

Results

Of the 150 patients screened, 78 patients were included in this retrospective analysis. Median age at diagnosis was 67 years (IQR 61-74 years). Forty one (53%) males and 37 (47%) females were included in the study. Forty two (53.8%) patients had positive anti-MPO antibodies, 29 (37.2%) had anti-PR3 antibodies and 7 (9.0%) had seronegative AAGN. 15 of 78 patients required dialysis or transplantation within the study period assessed.

KFRE was calculated at 6 months (± 3 months) ; the median 2 year risk KFRE score was 2% (IQR 0.3-5%) and median 5 year KFRE score was 7.1% (IQR 1.1-17.6%) (Fig. 1). KFRE was calculated at 18 months (± 3 months) ; the median 2 year risk KFRE score was 0.7% (IQR 0.4–2.7%) and median 5 year KFRE score was 2.1% (IQR 0.7–9.5%).

In terms of discrimination for KFRE calculated 6 months after diagnosis, in the 2 year analysis, the AUC was 0.74 (95% CI 0.55-0.92) and in the 5 year analysis, the AUC was 0.73 (95% CI 0.55-0.90). When KFRE was calculated 18 months after diagnosis, in the 2 year analysis, the AUC was 0.75 (95% CI 0.30-1) and in the 5 year analysis, the AUC was 0.81 (95% CI 0.50-1).

Conclusion

While KFRE is a thoroughly validated and widely adopted tool in CKD patients, its application in primary renal pathologies, such as AAGN, is yet to be determined. We have shown that KFRE provides fair discrimination, as early as 6 months after initial diagnosis and may provide future clinical utility in AAGN patients that have achieved stable remission. Current tools to risk stratify AAGN patients require histological parameters which is not always possible to achieve and further work in predicting the prognosis of glomerular diseases is needed. This study was limited by the single centre and small cohort but further analysis and validation on a larger multi-centre cohort is needed before KFRE can be considered for clinical use in AAGN patients.