Elevated serum osmolarity is associated with poor in-hospital prognosis in patients with cardiac arrest: A retrospective study based on MIMIC-IV database

Abstract Background A major cause of death is cardiac arrest (CA). Serum osmolarity has been shown to be useful in predicting the prognosis of sepsis patients in earlier research. The purpose of this study is to ascertain the impact of serum osmolarity on the prognosis of cardiac arrest patients in the intensive care unit. Methods In this study, the relationship between serum osmolarity and in-hospital mortality in ICU patients experiencing cardiac arrest was investigated. The MIMIC-IV database was used to select adult patients with cardiac arrest diagnoses for this investigation. The serum concentrations of Na⁺, K⁺, glucose, and urea nitrogen were used to determine the serum osmolarity simultaneously. Results The baseline data of adult patients with CA hospitalized in the intensive care unit (ICU) from 2008 to 2019 in the American Intensive Care Database (MIMIC-IV, version v2.0) were collected. In this study, the patients were divided into survival and non-survival group, according to the 28-day prognosis. The mortality in the hyper-osmolarity group (61.96%) was significantly higher than that in the normal osmolarity group (35.51%, P < 0.001). The Kaplan-Meier survival analysis before and after matching showed that the cumulative survival rate of the hyper-osmolarity was lower (P < 0.05). The Univariate and Multivariable COX analysis of risk factors for death (After PSM) shows that hyper-osmolarity was a significant independent risk factor for 28-day mortality. It was coincident with the result of subgroup analysis. Conclusion The serum osmolarity would be a predictive biomarker that is accessible right after a cardiac arrest for CA survivors. It can be determined more quickly and at a lower cost. However, more research is required to assess serum osmolality's prognostic value in various patient populations.