Figure 1 displays changes in serum creatinine and NGAL during the first week of admission in patients with and without WRF, adjusted for study treatment. Biomarker changes for alternative WRF definitions are presented as supplementary Figures S1 and S2, and display similar patterns. Serum creatinine and plasma NGAL trajectories differed significantly between patients with and without WRF for all definitions (p for interaction with time <0.001), and rolofylline treatment had no effect (p = n.s.). Figure 2 shows the relative creatinine and plasma NGAL changes over the first 7 days in patients with and without WRF. In patients who developed WRF, NGAL levels did not rise significantly sooner than creatinine levels; both markers increased in parallel over the first 2 days (p for difference n.s.), with NGAL rising further than creatinine over the course of 7 days, while displaying greater variability (p < 0.05). Patterns were similar for alternative definitions of WRF (Figures S3 and S4).