The association between albumin-corrected anion gap and in-hospital mortality in critically ill COPD patients: A multicenter retrospective study from eICU collaborative research database.

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) in the intensive care unit (ICU) often have poor prognoses. Early assessment of disease severity is crucial for timely interventions to improve outcomes. The albumin-corrected anion gap (ACAG) reflects the degree of metabolic acidosis and reduces the interference of hypoalbuminemia in the results, making it a suitable marker for COPD patients in the ICU. This study aims to explore the association between ACAG and in-hospital mortality in ICU patients with COPD.

METHODS

We extracted data from 4304 ICU-admitted COPD patients from the eICU Database and categorized them into four groups based on ACAG quartiles. Logistic regression models were used to analyze the relationship between ACAG and in-hospital mortality in critically ill COPD patients. Restricted cubic spline (RCS) was employed to further explore the potential non-linear association between ACAG and in-hospital mortality. Receiver operating characteristic (ROC) and decision curve analysis (DCA) were used to compare the predictive performance of ACAG and the anion gap. Subgroup analyses were performed to investigate potential interactions.

RESULTS

Higher ACAG levels were a strong predictor of in-hospital mortality in critically ill COPD patients. A non-linear relationship was observed between elevated ACAG levels and increased risk of in-hospital mortality, with a sharp increase in mortality risk when ACAG exceeded 15. Compared with the anion gap, ACAG demonstrated superior predictive ability. Subgroup analysis revealed that ACAG had a stronger predictive value in patients younger than 65 years.

CONCLUSIONS

ACAG is an effective predictor of in-hospital mortality in ICU patients with COPD, offering better predictive power than the anion gap. ACAG can assist in early disease monitoring and risk stratification in critically ill COPD patients.