Abstract: FR-PO0853
Urine Albumin-to-Creatinine Ratio and Protein-to-Creatinine to Predict Kidney Failure Rates in Patients with Glomerular and Nonglomerular Diseases in the UK National Registry of Rare Kidney Diseases (RaDaR) Cohort
Session Information
- Glomerular Outcomes: From Proteinuria to Prognosis
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Wong, Katie, National Registry of Rare Kidney Diseases, Bristol, United Kingdom
- Pitcher, David, National Registry of Rare Kidney Diseases, Bristol, United Kingdom
- Rogers, Dane J, National Registry of Rare Kidney Diseases, Bristol, United Kingdom
- Gale, Daniel P., University College London Faculty of Medical Sciences, London, United Kingdom
Background
Proteinuria is associated with long term kidney failure (KF) risk. However, whether the predictive value of proteinuria as assessed by urine albumin:creatinine ratio (ACR) is different to urine protein:creatinine ratio (PCR), and whether ACR:PCR conversion rates differ between glomerular and non-glomerular kidney diseases is unknown. We addressed this evidence gap using long term renal survival data from the UK National Registry of Rare Kidney Diseases (RaDaR).
Methods
ACR to PCR conversion rates were estimated for individual rare diseases using data from patients with same day ACR and PCR measurements available, for all results and restricted to values with PCR<50mg/mmol. Mixed models were used to account for repeated measures and adjusted for age, sex, ethnicity and CKD stage. KF was defined as sustained eGFR<15mL/min/1.73m2, Kidney Replacement Therapy initiation or death. KF survival was modelled using Cox regression, adjusted for age, sex, CKD stage and CV risk markers at index. Each proteinuria metric was log-transformed and included separately, and model fit was assessed using AIC (Akaike information criterion) statistics where a smaller value indicates better fit, by glomerular and non glomerular disease. Hazard ratios (HRs) associated with a one unit increase in the standard deviation of each log-transformed proteinuria metric are presented.
Results
3993 participants were included in these analyses, n=2957 with glomerular disease, n=981 with non-glomerular disease (predominantly ADPKD). ACR:PCR conversion rates varied by kidney disease (Alport syndrome: 0.7003, ADPKD: 0.5191), and were lower when restricted to PCR values <50mg/mmol for all groups. There were no major differences in HRs of time to KF when using ACR or PCR (Figure 1), or in AIC value between glomerular (ACR AIC 1279.0, PCR AIC 1285.2) and non-glomerular groups (ACR AIC 202.97, PCR AIC 202.47)
Conclusion
Whilst most CKD guidelines recommend ACR as biomarker of choice in early disease, these results do not show superiority of PCR or ACR in assessing proteinuria in rare kidney disease cohorts.