CRP and chronic obstructive pulmonary disease: The area under the curve (AUC) for total bilirubin in predicting COPD exacerbation was 0.607 (95% CI: 0.531–0.736); for blood uric acid, the AUC was 0.734 (95% CI: 0.642–0.821); and for CRP, the AUC was 0.613 (95% CI: 0.531–0.745).