To analyze risk factors for death at 28 days after return of spontaneous circulation (ROSC) in adult non-traumatic out-of-hospital cardiac arrest (OHCA) patients and to develop a nomogram model.

A total of 134 patients with non-traumatic OHCA and ROSC admitted to the emergency rescue room at the Fourth Affiliated Hospital, Zhejiang University School of Medicine from October 22, 2015 to June 30, 2022 were included. According to their death status within 28 days after ROSC, all patients were divided into a survival group (45 cases) and a death group (89 cases). Clinical data of the two groups were collected and univariate analysis was performed. Independent variables were screened by optimal subset regression analysis with minimum Bayesian information criterion (BIC) values. Multivariate logistic regression analysis was used to identify independent risk factors for death at 28 days after ROSC, and a nomogram prediction model was constructed. The receiver operating characteristic (ROC) curve, calibration curve and decision curve analysis were used to evaluate the nomogram model. Finally, the area under the curve (AUC) of acute physiology and chronic health evaluation (APACHE) Ⅱ score and the nomogram model was compared.

Multivariate logistic regression showed that blood potassium [odds ratio (OR) = 1.454, 95% confidence interval (CI) (1.007, 2.098), P = 0.046], creatine kinase isoenzyme MB (CK-MB) [OR = 1.024, 95%CI (1.008, 1.041), P = 0.004], uric acid [OR = 1.005, 95%CI (1.001, 1.010), P = 0.013] and adrenaline dosage [OR = 1.282, 95%CI (1.080, 1.522), P = 0.004] were independent risk factors for death at 28 days after ROSC in non-traumatic OHCA patients, and the shockable rhythm was a protective factor [OR = 0.054, 95%CI (0.014, 0.211), P < 0.001]. Based on the above risk factors, a nomogram was constructed for predicting mortality risk of OHCA patients. The AUC of the nomogram was 0.872 [95%CI (0.812, 0.932), P < 0.001]. The calibration curve showed that the predicted and actual probabilities were consistent, and the decision curve analysis showed that the nomogram had a good clinical benefit. In addition, the AUC and 95%CI of APACHEⅡ score was 0.773 (0.688, 0.858), with P < 0.001, and the AUC of the nomogram model was significantly better than that of the APACHEⅡ score (Z = 1.994, P = 0.046).

The shockable rhythm, the dosage of adrenaline, and the first blood potassium, blood uric acid and CK-MB after admission to the emergency department are independent influencing factors for 28-day mortality in non-traumatic OHCA patients after ROSC. The prediction model based on the above factors has a good clinical practical value.