CST3 and respiratory failure: Multivariate logistic regression analysis revealed that serum Cystatin C (odds ratio [OR] 4.27, 95% confidence interval [CI] 3.36–5.44; p < 0.001), acute respiratory failure (OR 3.96, 95% CI 2.29–3.83; p < 0.001), albumin (OR 0.91, 95% CI 0.89–0.94; p < 0.001), uric acid (OR 1.002, 95% CI 1.001–1.003; p < 0.001), platelet count (OR 0.997, 95% CI 0.996–0.998; p = 0.001), white blood cell count (OR 1.08, 95% CI 1.05–1.10; p < 0.001), and CURB-65 score were independent factors for AKI in patients with CAP (Table 2).