The association between albumin-corrected calcium and prognosis in patients with cardiac arrest: a retrospective study based on the MIMIC-IV database

Background Cardiac arrest (CA) is one of the leading causes of death globally, characterized by high incidence and mortality. It is of particular significance to determine the prognosis of patients with CA early and accurately. Therefore, we aim to investigate the correlation between albumin-corrected calcium (ACC) and the prognosis in patients diagnosed with CA. Methods We retrospectively collected data from medical information mart for intensive care IV database. Patients were divided into two groups (survival and non-survival groups), according to the 90-day prognosis. In the Restricted cubic spline (RCS) analysis, the cut-off values (8.86 and 10.32) were obtained to categorize patients into three groups: low ACC group (< 8.86), moderate ACC group (8.86-10.32), and high ACC group (> 10.32). The least absolute shrinkage and selection operator with a ten-fold cross-validation regression analysis was performed to identify variables linked to the mortality. The inverse probability treatment weighting (IPTW) was used to address the confounding factors, and a weighted cohort was generated. RCS, Kaplan-Meier curve, and Cox regression analyses were used to explore the relationship between ACC and the mortality. Sensitivity analysis was employed to validate the stability of the results. Results Cut-off values for ACC of 8.86 and 10.32 were determined. RCS analyses showed that there was an overall non-linear trend relationship between ACC and the risk of 90-day and 360-day mortalities. After IPTW adjustment, compared to the moderate ACC group, the 90-day and 360-day mortalities in the high ACC group were higher (P < 0.05). The Cox analyses before and after IPTW adjustment showed that both low ACC and high ACC group were independent risk factors for 90-day and 360-day all-cause mortality in patients with CA (P < 0.05). The results obtained from sensitivity analyses indicated the stability of the findings. The Kaplan-Meier survival curves indicated that 90- and 360-day cumulative survival rates in the low ACC and high ACC groups were lower than that in the moderate ACC group (chi(2) = 11.350, P = 0.003; chi(2) = 14.110, P = 0.001). Conclusion Both low ACC (< 8.86) and high ACC groups (> 10.32) were independent risk factors for 90-day and 360-day all-cause mortality in patients with CA (P < 0.05). For those CA patients with high and low ACC, it deserved the attention of clinicians.