Clinical Utility of 4C Mortality Scores among Japanese COVID‐19 Patients: A Multicenter Study

Background: We analyzed data from COVID‐19 patients in Japan to assess the utility of the 4C mortality score as compared with conventional scorings. Methods: In this multicenter study, COVID‐19 patients hospitalized between March 2020 and June 2021, over 16 years old, were re-cruited. The superiority for correctly predicting mortality and severity by applying the receiver operating characteristic (ROC) curve was compared. A Cox regression model was used to compare the length of hospitalization for each risk group of 4C mortality score. Results: Among 206 patients, 21 patients died. The area under the curve (AUC) (95% confidential interval (CI)) of the ROC curve for mortality and severity, respectively, of 4C mortality scores (0.84 (95% CI 0.76–0.92) and 0.85 (95% CI 0.80–0.91)) were higher than those of qSOFA (0.66 (95% CI 0.53–0.78) and 0.67 (95% CI 0.59–0.75)), SOFA (0.70 (95% CI 0.55–0.84) and 0.81 (95% CI 0.74–0.89)), A‐DROP (0.78 (95% CI 0.69–0.88) and 0.81 (95% CI 0.74–0.88)), and CURB‐65 (0.82 (95% CI 0.74–0.90) and 0.82 (95% CI 0.76–0.88)). For length of hospitalization among survivors, the intermediate‐ and high‐ or very high‐risk groups had significantly lower hazard ratios, i.e., 0.48 (95% CI 0.30–0.76)) and 0.23 (95% CI 0.13–0.43) for dis-charge. Conclusions: The 4C mortality score is better for estimating mortality and severity in COVID‐19 Japanese patients than other scoring systems.