The patients with AKI requiring RRT, comparing with the patients with AKI not requiring RRT, had significant higher PSI (142.0 ± 46.2 vs. 120.6 ± 45.4, p value = 0.025), APACHE II score (29.5 ± 8.1 vs. 23.4 ± 7.4, p value < 0.001), SOFA score (13.9 ± 3.5 vs. 10.3 ± 3.8, p value < 0.001), C-reactive protein (19.4 ± 10.2 vs. 14.9 ± 10.3, p value = 0.041), peak airway pressure (31.6 ± 5.1 vs. 29.1 ± 4.7, p value = 0.028), and significant poorer PaO2/FiO2 ratio (82.4 ± 46.7 vs. 105.7 ± 62.0, p value = 0.037). This evidence concerns the gene CRP and acute kidney injury.