External validation and comparison of the CardShock and IABP-SHOCK II risk scores in real-world cardiogenic shock patients

Abstract Background Mortality from cardiogenic shock remains high and early recognition and risk stratification are mandatory for optimal patient allocation and to guide treatment strategy. The CardShock and the Intra-Aortic Balloon Counterpulsation in Acute Myocardial Infarction Complicated by Cardiogenic Shock (IABP-SHOCK II) risk scores have shown good results in predicting short-term mortality in cardiogenic shock. However, to date, they have not been compared in a large cohort of ischaemic and non-ischaemic real-world cardiogenic shock patients. Methods The Red-Shock is a multicentre cohort of non-selected cardiogenic shock patients. We calculated the CardShock and IABP-SHOCK II risk scores in each patient and assessed discrimination and calibration. Results We included 696 patients. The main cause of cardiogenic shock was acute coronary syndrome, occurring in 62% of the patients. Compared with acute coronary syndrome patients, non-acute coronary syndrome patients were younger and had a lower proportion of risk factors but higher rates of renal insufficiency; intra-aortic balloon pump was also less frequently used (31% vs 56%). In contrast, non-acute coronary syndrome patients were more often treated with mechanical circulatory support devices (11% vs 3%, p<0.001 for both). Both risk scores were good predictors of in-hospital mortality in acute coronary syndrome patients and had similar areas under the receiver-operating characteristic curve (area under the curve: 0.742 for the CardShock vs 0.752 for IABP-SHOCK II, p=0.65). Their discrimination performance was only modest when applied to non-acute coronary syndrome patients (0.648 vs 0.619, respectively, p=0.31). Calibration was acceptable for both scores (Hosmer-Lemeshow p=0.22 for the CardShock and 0.68 for IABP-SHOCK II). Conclusions In our cohort, both the CardShock and the IABP-SHOCK II risk scores were good predictors of in-hospital mortality in acute coronary syndrome-related cardiogenic shock.