Association of serum anion gap and risk of long-term mortality in patients following coronary artery bypass grafting: A propensity score matching study

The correlation between albumin-corrected anion gap and prognosis in patients with acute myocardial infarction

AIMS

Acute myocardial infarction (AMI) is a cardiovascular disease with high morbidity and mortality. We collected patients with AMI from the Medical Information Mart for Intensive Care IV (v2.0) database and explored the association between serum albumin-corrected anion gap (ACAG) level and mortality in patients with AMI.

METHODS AND RESULTS

Data of adult patients with AMI were collected. According to the 360 day prognosis, patients were divided into survival and non-survival groups. Based on the ACAG level, patients were then divided into normal and high ACAG groups. Cox hazard proportional models and restricted cubic splines (RCSs) were used to investigate the correlation between ACAG and mortality. Kaplan-Meier curves were created to compare the cumulative survival rates between the high and normal ACAG groups. The receiver operating characteristic (ROC) curve was used to analyse the predictive value of ACAG for the prognosis of patients with AMI. Sensitivity and subgroup analyses were conducted to revalidate the results. Finally, 1783 patients were included. Elevated ACAG (>20 mmol/L) was significantly associated with 30 and 360 day mortality (P < 0.001). Adjusted for multiple confounding factors, the Cox proportional hazard analysis showed that elevated ACAG (>20 mmol/L) was an independent risk factor of increased all-cause mortality in patients with AMI (hazard ratio 1.423, 95% confidence interval 1.206-1.678, P < 0.001). RCS analysis further showed that there was a non-linear trend relationship between ACAG and the risk of all-cause mortality at 30 and 360 days (χ2 = 10.750, P = 0.013; χ2 = 13.960, P = 0.003). Kaplan-Meier survival curves showed that the 30 and 360 day cumulative survival rates of patients with AMI were significantly lower (log-rank test, χ2 = 98.880, P < 0.001; χ2 = 105.440, P < 0.001) in the high ACAG group. ROC curve analysis showed that the area under the curve (AUC) of ACAG was 0.651, while the AUC of anion gap (AG) was 0.609, indicating that ACAG had a higher predictive value for 360 day mortality than AG. When combined with Sequential Organ Failure Assessment score, the predictive performance of ACAG for 360 day mortality was better, with an AUC of 0.699. Sensitivity and subgroup analyses were conducted suggesting the stability of our results.

CONCLUSIONS

Elevated serum ACAG (≥20 mmol/L) is an independent risk factor for short-term and long-term mortality in critically ill patients with AMI, and it may assist clinicians and nurses identifying high-risk patients.

Association between serum anion gap and all-cause mortality in patients with acute myocardial infarction: A retrospective study based on MIMIC-IV database

Background

Although previous studies have reported that many biomarkers can determine the prognosis of patients with acute myocardial infarction (AMI), serum anion gap (AG) has not been well studied. We aimed to investigate the association between serum AG and mortality in patients with AMI.

Methods

Adult patients first admitted to the ICU and diagnosed with AMI from 2008 to 2019 in the MIMIC-IV database were included. Patients were divided into the survival and non-survival groups based on 30-day and 90-day outcomes. According to the AG value (15.12 mmol/L) with a hazard ratio of 1 in the restricted cubic spline (RCS) analysis, patients were further divided into high and low AG groups. The Kaplan-Meier survival curve was plotted, and all-cause mortality was compared between the high and low groups using the log-rank test. Multivariate Cox regression analysis and RCS analysis were constructed to assess the relationship between AG and recent all-cause mortality in patients with AMI.

Results

4446 patients were enrolled. The 30-day and 90-day mortality rates in the high AG group (25.53%, 31.75%) were higher than that in the low AG group (9.73%, 14.01%, P < 0.001) independently. The Kaplan-Meier curve showed that the 30-day and 90-day cumulative survival rates were lower in the high AG group than that in the low AG group (P < 0.001). RCS analysis showed that there was a non-linear relationship between AG and the risk of 90-day all-cause mortality in patients with AMI (χ2 = 18.680 P < 0.001). When AG was 15.12 mmol/L, its HR was about 1. Multivariable Cox regression analysis confirmed that increased AG was associated with higher 30-day and 90-day mortality.

Conclusion

Elevated serum AG (≥15.12 mmol/L) is an independent predictor for short-term mortality in patients with AMI, and it may provide a basis for clinicians to identify patients with poor prognosis as early as possible.