Association between albumin corrected anion gap (ACAG) and all-cause mortality in intensive care unit heart failure patients treated with inotropes and vasopressors

Background: To eliminate the influence of serum albumin level on anion gap, the albumin-corrected anion gap (ACAG) is introduced into clinic. There is increasing evidence suggesting that ACAG functions as an early prognostic indicator in patients with cardiovascular diseases and critical illnesses. However, as a novel parameter, many aspects of its clinical utility remain uncertain. In particular, the relationship between ACAG and the risk of in-hospital mortality in intensive care unit (ICU) heart failure patients treated with inotropes or vasopressors and whether ACAG could enhance sequential organ failure assessment (SOFA) and acute physiology score Ⅲ (APS Ⅲ) scores remains inconclusive. Methods: This study assessed patients with heart failure requiring inotropes or vasopressors from the eICU Collaborative Research Database (eICU-CRD) and the Medical Information Mart for Intensive Care Ⅳ database (MIMIC-Ⅳ). Results: Analysis of eICU-CRD data revealed that elevated ACAG was independently associated with all-cause mortality, with odds ratios of 1.14 (95%confidence interval (CI), 1.09–1.18), 1.41 (95% CI, 1.36–1.47), and 2.29 (95% CI, 2.20–2.38) for Q2 to Q4 groups compared to the lowest quartile for ACAG. The restricted cubic spline regression demonstrated a linear relationship, which remained consistent across various subgroups (p for interaction > 0.05 for all). Analysis of MIMIC-Ⅳ data indicated that the inclusion of ACAG significantly enhanced the prognostic value based on SOFA and APS Ⅲ. In addition, the area under the curve for SOFA increased from 0.740 to 0.772 (p < 0.001), and for APS Ⅲ increased from 0.815 to 0.824 (p < 0.001). Conclusions: ACAG was shown to be independently associated with the risk of all-cause mortality in heart failure patients requiring inotropes or vasopressors in the ICU, and it could serve as a potent supplement to SOFA and APS Ⅲ.

Anion gap; Heart failure; Intensive care unit; Mortality

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