However, Day 1 intact FGF23 levels did not significantly differ between the two groups (median 28 [IQR 13, 105] pg/ml in the AKI group vs. median 21 [IQR 11, 41] pg/ml in the non-AKI group, p = 0.09) (Fig 2B). Here, FGF23 is linked to acute kidney injury.