Abstract
INTRODUCTION: Total kidney volume (TKV) interpreted via the Mayo Imaging Classification (MIC) is the recommended prognostication tool in autosomal dominant polycystic kidney disease (ADPKD), but further risk stratification is often needed. The kidney failure risk equation (KFRE) is validated in chronic kidney disease (CKD) of diverse etiologies, but its use in patients with ADPKD already assessed via the MIC is unclear. This study evaluated the impact of adding KFRE to MIC. METHODS: Adults with ADPKD with ≥1 computed tomography (CT) or magnetic resonance imaging (MRI) derived TKV available between January 2015 and January 2023 were included in this retrospective observational study. The predictive performance of models including the MIC value, baseline estimated glomerular filtration rate (eGFR), and 5-year KFRE score, and fully adjusted models were examined using the composite outcome of kidney replacement therapy initiation or eGFR decline 40%. The primary analysis was in patients with eGFR < 60 ml/min per 1.73 m(2). RESULTS: In the eGFR < 60 ml/min per 1.73 m(2) group, compared with the model showing MIC value alone, the adjusted model including age, sex, tolvaptan, KFRE, and MIC value demonstrated the best performance (Akaike information criterion [AIC] = 631, ΔC-statistic = 0.47, 0.28, and 0.27 at 1, 3, and 5 years respectively), followed closely by the combination of MIC value and KFRE (AIC = 641, ΔC-statistic = 0.47, 0.26, and 0.26), KFRE alone (AIC = 642, ΔC-statistic = 0.47, 0.26, and 0.28) at 1, 3, and 5 years respectively. CONCLUSION: In the cohort with a baseline eGFR < 60 ml/min per 1.73 m(2), use of the KFRE in addition to the MIC improved risk prediction, supporting the utilization of these tools together in ADPKD.