FGF23 and acute kidney injury: After adjustment for Day 1 covariates (age, sex, presence/absence of AKI, P/F ratio, and PRISM score), Day 1 total FGF23 levels remained significantly associated with 60-day mortality (OR 1.62 [95% CI 1.07, 2.45], p = 0.023), but Day 1 intact FGF23 levels did not (OR 1.30 [95% CI 0.89, 1.90], p = 0.17) (Table 3, Model 2).