Supplementary Material for: Urinary Kringle Domain-Containing Protein HGFL: A Validated Biomarker of Early Sickle Cell Anemia-Associated Kidney Disease

Introduction: Chronic kidney disease (CKD) is a prevalent complication of sickle cell anemia (SCA). Hyperfiltration that delayed detection of CKD is common in SCA patients. Identification of novel urinary biomarkers correlating with glomerular filtration rates may help to detect and predict progression of renal disease. Methods: Reanalysis of mass spectra of urinary samples obtained from University of Illinois at Chicago identified kringle domain-containing protein HGFL. Results: HGFL levels correlated with hyperfiltration, were significantly reduced at CKD stage 1 compared to stage 0, negatively correlated with progression of CKD and were suitable for differentiation of stage 1. Better prediction of CKD progression to stage 2 was observed for HGFL-based risk prediction compared to the estimated glomerular filtration rate (eGFR)-based prediction. Results from a Howard University patient cohort supported the utility of HGFL-based test for the differentiation of stage 1 of CKD. Conclusion: Urinary HGFL may contribute additional information beyond eGFR and improve diagnosis of early-stage CKD in SCA patients.