Objective: Serum bicarbonate (HCO3⁻) level is strongly related to multiple cardiovascular complications. Currently, there is no study evaluating the prognostic ability of serum HCO3⁻ level in intensive care unit (ICU) patients with acute aortic dissection (AAD). Hence, this study was to assess the relationship between admission serum HCO3⁻ level and clinical outcomes in patients with AAD.
Design, Settings and Participants: Clinical data were extracted from the MIMIC-III database. Cox proportional hazards models and Kaplan–Meier (KM) survival curve were used to evaluate the association between serum HCO3⁻ levels and short- and long-term mortality in ICU patients with AAD. The subgroup analysis and the receiver operating characteristic (ROC) curve analysis and further KM survival curve based on best cut-off value were applied to assessment of the performance of HCO3⁻ in predicting the mortality in each period (30 days, 90 days, 1 year and 5 years).
Main Results: Firstly, 336 eligible patients were trisected to low-HCO3⁻ level group (< 22 mmol/L), mid-HCO3⁻ level group (22– 24 mmol/L) and high-HCO3⁻ level group (> 24 mmol/L). Then, in multivariate analysis, the serum HCO3⁻ of low levels (< 22 mmol/L) was a significant risk predictor of all-cause mortality in 30 days, 90 days, 1 year and 5 years. Subgroup analyses indicated that there is no interaction in most strata. Finally, areas under ROC curve ranged from 0.60 to 0.69.
Conclusion: The low HCO3⁻ serum level measured at ICU admission significantly predicts short-term and long-term mortality in AAD patients.
Keywords: serum bicarbonate, intensive care unit, acute aortic dissection, all-cause mortality