Figure 5.

Receiver operating characteristic curves for hypohydration measures in discriminating positive acute kidney injury (AKI) risk. Positive AKI risk was determined as urinary product of insulin-like growth factor-binding protein 7 and tissue inhibitor of metalloproteinase-2 ([IGFBP7·TIMP-2]) > 0.3 (ng/mL)²/1,000. The line of identify represents random chance. Area under the curve (AUC) values are reported as means with 95% confidence intervals and P values from statistical comparison with random chance. AUC was compared using the nonparametric method of Delong et al. (63). AUCs for all hypohydration measures were statistically different from random chance (P ≤ 0.0240). *AUC different from the change in body mass (Δbody mass) (P ≤ 0.0097); †AUC different from serum osmolality (P = 0.0240); ‡AUC different from serum Na⁺ (P ≤ 0.0193). A–F: body mass (A), urine color (B), urine specific gravity (C), urine osmolality (D), serum osmolality (E), and serum sodium (F).