Volume 89, Issue 4, Pages 939-948 (April 2016) Fibroblast growth factor 23 levels are elevated and associated with severe acute kidney injury and death following cardiac surgery  David E. Leaf, Marta Christov, Harald Jüppner, Edward Siew, T. Alp Ikizler, Aihua Bian, Guanhua Chen, Venkata S. Sabbisetti, Joseph V. Bonventre, Xuan Cai, Myles Wolf, Sushrut S. Waikar  Kidney International  Volume 89, Issue 4, Pages 939-948 (April 2016) DOI: 10.1016/j.kint.2015.12.035 Copyright © 2016 International Society of Nephrology Terms and Conditions

Figure 1 Kinetics of plasma C-terminal fibroblast growth factor 23 (cFGF23) in acute kidney injury (AKI) versus no AKI. (a) cFGF23 levels overall and stratified by (b) pre-existing chronic kidney disease (CKD) or (c) no pre-existing CKD. P values in boxes are from repeated-measures mixed linear models comparing the 2 curves. *P < 0.05, **P ≤ 0.01, and ***P < 0.001; comparison of cFGF23 levels at individual time points in patients with or without AKI, defined as an increase in serum creatinine levels to ≥0.3 mg/dl within 48 hours or ≥50% in 7 days. Data are shown as median (interquartile range). End CPB, end of cardiopulmonary bypass; POD, postoperative day; RU, relative units. Kidney International 2016 89, 939-948DOI: (10.1016/j.kint.2015.12.035) Copyright © 2016 International Society of Nephrology Terms and Conditions

Figure 2 Plasma C-terminal fibroblast growth factor 23 (cFGF23), serum creatinine, and urinary tubular injury markers in patients with no acute kidney injury (AKI), mild AKI, and severe AKI after cardiac surgery. (a) cFGF23 levels, (b) serum creatinine levels, and (c–e) urinary tubular injury marker levels. P values in boxes are from repeated-measures mixed linear models comparing the 3 curves. **P < 0.01, and ***P < 0.001; comparison of biomarker levels across AKI categories at individual time points. Data are shown as median (interquartile range). End CPB, end of cardiopulmonary bypass; KIM-1, kidney injury molecule-1; NAG, n-acetyl-ß-(D)-glucosaminidase; NGAL, neutrophil gelatinase-associated lipocalin; POD, postoperative day; RU, relative units. Kidney International 2016 89, 939-948DOI: (10.1016/j.kint.2015.12.035) Copyright © 2016 International Society of Nephrology Terms and Conditions

Figure 3 Plasma C-terminal fibroblast growth factor 23 (cFGF23), intact FGF23 (iFGF23), and their ratio in severe acute kidney injury (AKI) versus no AKI. (a) cFGF23 levels, (b) iFGF23 levels, and (c) ratio of cFGF23 to iFGF23. P values in boxes are from repeated-measures mixed linear models comparing the 2 curves. *P < 0.05, **P < 0.01, and ***P < 0.001; comparison of biomarker levels at individual time points in patients with severe AKI versus no AKI. The ratio of cFGF23 to iFGF23 was calculated as follows: (cFGF23 – iFGF23)/iFGF23. Data shown as median (interquartile range). End CPB, end of cardiopulmonary bypass; POD, postoperative day; RU, relative units. Kidney International 2016 89, 939-948DOI: (10.1016/j.kint.2015.12.035) Copyright © 2016 International Society of Nephrology Terms and Conditions

Figure 4 Plasma parathyroid hormone (PTH), phosphate, and vitamin D metabolites in severe acute kidney injury (AKI) versus no AKI. (a) PTH levels, (b) phosphate levels, and (c–e) vitamin D metabolite levels. P values in boxes are from repeated-measures mixed linear models comparing the 2 curves. *P < 0.05, **P < 0.01, and ***P < 0.001; comparison of biomarker levels at individual time points in patients with severe AKI versus no AKI. Data are shown as median (interquartile range). 1,25D, 1,25-dihydroxyvitamin D; 25D, 25-hydroxyvitamin D; 24,25D, 24,25-dihydroxyvitamin D; End CPB, end of cardiopulmonary bypass; POD, postoperative day. Kidney International 2016 89, 939-948DOI: (10.1016/j.kint.2015.12.035) Copyright © 2016 International Society of Nephrology Terms and Conditions