Multivariate analysis demonstrated that longer RRT duration (7.0 vs. 9.6 d, p = 0.002, OR = 0.94, 95%CI: 0.92–0.96), higher C-reactive protein levels (73.8 vs. 109.4 mg/L, p = 0.003, OR = 0.91, 95%CI: 0.90–0.92), elevated serum cystatin C (1.2 vs. 3.2 mg/L, p < 0.001, OR = 0.46, 95%CI: 0.40–0.53), septic shock (28.1% vs. 41.5%, p < 0.001, OR = 0.63, 95%CI: 0.45–0.89), and a history of invasive procedures (36.7% vs. 55.7%, p < 0.001, OR = 0.33, 95%CI: 0.25–0.46) were associated with a reduced likelihood of successful RRT weaning. The gene discussed is CST3; the disease is septic shock.