The association between serum anion gap and all-cause mortality of unselected adult patients: A retrospective cohort study of >20,000 patients

Increased serum albumin corrected anion gap levels are associated with poor prognosis in septic patients with liver cirrhosis

The prognosis of septic patients with cirrhosis is worse compared to septic patients without cirrhosis. Early and accurate prognosis determination in patients with cirrhosis and sepsis is pivotal for guiding treatment decisions. The aim of this study was to investigate the association between albumin-corrected anion gap (ACAG) and clinical prognosis of patients with sepsis and cirrhosis. This study extracted data of patients with sepsis and cirrhosis from the Medical Information Mart for Intensive Care (MIMIC-IV) database. A total of 1340 patients (64.6% male) were enrolled. After confounders adjusting, elevated ACAG had a significant association with 28-day mortality (HR1.604; 95% CI 1.258-2.048; P < 0.001). Restricted cubic spline revealed that a linear relationship between ACAG and 28-day mortality (P-nonlinear = 0.089, P-overall = 0.001). According to the ROC curve analysis, the ACAG demonstrated a higher area under the curve (AUC) of 0.703 compared to AG (0.675). Kaplan-Meier analysis revealed higher 28-day mortality in high ACAG group (log-rank test, χ^2 = 175.638, P < 0.001). Furthermore, subgroup analysis showed a significant interaction between ACAG and etiology of cirrhosis (P for interaction = 0.014). Therefore, ACAG could provide clinicians with valuable insights for guiding interventions in this high-risk population.

The relationship between serum anion gap levels and short-, medium-, and long-term all-cause mortality in ICU patients with congestive heart failure: a retrospective cohort study

BACKGROUND

There hasn't been research done on the connection between serum anion gap (AG) levels and long-, medium-, and short-term all-cause mortality in congestive heart failure (CHF) patients. This study aims to investigate the association between serum anion gap levels and all-cause mortality in CHF patients after adjusting for other covariates.

METHODS

For each patient, we gather demographic information, comorbidities, laboratory results, vital signs, and scoring data using the ICU (Intensive Care Unit) Admission Scoring System from the MIMIC-III database. The connection between baseline AG and long-, medium-, and short-term all-cause mortality in critically ill congestive heart failure patients was investigated using Kaplan-Meier survival curves, subgroup analysis, restricted cubic spline, and Cox proportional risk analysis.

RESULTS

4840 patients with congestive heart failure in total were included in this study. With a mean age of 72.5 years, these patients had a gender split of 2567 males and 2273 females. After adjusting for other covariates, a multiple regression analysis revealed that, in critically ill patients with congestive heart failure, all-cause mortality increased significantly with rising AG levels. In the fully adjusted model, we discovered that AG levels were strongly correlated with 4-year, 365-day, 90-day, and 30-day all-cause mortality in congestive heart failure patients with HRs (95% CI) of 1.06 (1.04, 1.08); 1.08 (1.05, 1.10); and 1.08 (1.05, 1.11) (p-value < 0.05). Our subgroup analysis's findings demonstrated a high level of consistency and reliability. K-M survival curves demonstrate that high serum AG levels are associated with a lower survival probability.

CONCLUSION

Our research showed the association between CHF patients' all-cause mortality and anion gap levels was non-linear. Elevated anion gap levels are associated with an increased risk of long-, medium-, and short-term all-cause death in patients with congestive heart failure. Continuous monitoring of changes in AG levels may have a clinical predictive role.

Association between Albumin-Corrected Anion Gap and Mortality in Patients with Cardiogenic Shock

Background

Cardiogenic shock (CS) is a critical illness with a high mortality rate in clinical practice. Although some biomarkers have been found to be associated with mortality in patients suffering from CS in previous studies. The albumin-corrected anion gap (ACAG) has not been studied in depth. Our study aimed to explore the relationship between ACAG and mortality in patients with CS.

Methods

All baseline data was extracted from Medical Information Mart for Intensive Care-IV version: 2.0 (MIMIC-IV). According to the prognosis at 30 days of follow-up, they were divided into survivors and non-survivors groups. The survival curves between the two groups were drawn using the Kaplan-Meier method and the log-rank test. Valid factors were selected using the least absolute shrinkage and selection operator (LASSO) logistic analysis model. Analysis was performed to investigate the relationship between mortality and all enrolled patients using restricted cubic spline (RCS) and Cox proportional hazards models. Receiver operating characteristic (ROC) curves were used to assess the predictive ability of ACAG. Evaluation of final result stability using sensitivity analysis.

Results

839 cases were selected to meet the inclusion criteria and categorized into survivors and non-survivors groups in the final analysis. The ACAG value measured for the first time at the time of admission was selected as the research object. Kaplan-Meier (K-M) survival curves showed that cumulative 30- and 90-day survival decreased progressively with elevated ACAG (p < 0.001), and multifactorial Cox regression analyses showed ACAG to be an independent risk factor for increased 30- and 90-day mortality in patients suffering from CS (p < 0.05). RCS curves revealed that all-cause mortality in this group of patients increased with increasing ACAG ( χ 2 = 5.830, p = 0.120). The ROC curve showed that the best cutoff value for ACAG for predicting 30-day mortality in patients with CS was 22.625, with a sensitivity of 44.0% and a specificity of 74.7%. The relationship between ACAG and CS short-term mortality remained stable in all sensitivity analyses (All p < 0.05).

Conclusions

The ACAG is an independent risk factor for 30- and 90-day mortality in CS patients and predicts poor clinical outcomes in CS patients. According to our study, elevated ACAG at admission, especially when ACAG > 20 mmol/L, was an independent predictor of all-cause mortality in CS.

Dynamics of serum anion gaps with in-hospital mortality: Analysis of the multi-open databases

BACKGROUND

Few studies have investigated the relationship between the anion gap, including the corrected anion gap, and patient mortality in intensive care units (ICUs) without restricting the analysis to specific diseases or medical specialties. Our primary objective was to investigate the association between the anion gap and ICU mortality using multiple open-access databases.

METHODS

We identified 4229 subjects from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database, whose entries were from between 2008 and 2019. For each patient, the anion gap and corrected anion gap were calculated, and the study sample was divided into tertile groups (T) according to these levels. The association between the anion gap and in-hospital mortality was assessed using hazard ratios (HRs) and 95% confidence intervals (CIs) derived from a multivariable-adjusted Cox proportional hazards model. Besides MIMIC-IV, we also incorporated study samples from two other databases (MIMIC-III and electronic ICU) to calculate summary HRs using a random-effects meta-analysis.

RESULTS

Within MIMIC-IV, 1015 patients (24%) died during an average follow-up period of 15.5 days. The fully adjusted HRs and 95% CIs for T2 and T3, relative to T1, were 1.31 (95% CI 1.08-1.58) and 1.54 (95% CI 1.24-1.90), respectively. When grouped by corrected anion gap, the results remained statistically significant. In the meta-analysis, the summary HRs and 95% CIs for T2 and T3 were 1.24 (95% CI 1.08-1.43) and 1.55 (95% CI 1.33-1.82), respectively.

CONCLUSIONS

Both the anion gap and corrected anion gap were associated with in-hospital mortality regardless of specific diseases or medical specialties.

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.

The relationship between preoperative anemia and length of hospital stay among patients undergoing radical surgery for esophageal carcinoma: a single-centre retrospective study

BACKGROUND

Although it is unclear if preoperative anemia affects patients undergoing radical resection of esophageal cancer, it does increase the length of stay (LOS) for surgical patients. Accordingly, the purpose of this study was to investigate if, after adjusting for other covariates, anemia was independently associated with LOS in people undergoing radical resection of esophageal cancer.

METHODS

The retrospective cohort study included 680 patients undergoing radical esophageal cancer surgery between January 2010 and December 2020. Preoperative anemia was the targeted independent variable, while LOS was the target independent variable. Demographics, comorbidities, laboratory tests, surgery and anesthesia, postoperative outcomes, and complications were collected. Multivariate linear analyses were performed for variables that might influence preoperative anemia and LOS selection. Subgroup analysis using hierarchical variables was then used to test the potential relationship.

RESULTS

The 647 individuals that were randomly chosen had an average age of 61.06 ± 8.16 years, and 77.43% of them were male. The prevalence of anemia was 36.6%. All patients recruited had an average length of stay (LOS) of 26.31 ± 13.19 days, 25.40 ± 11.44 days for patients who had no preoperative anemia, and 27.89 ± 15.66 days for patients who had preoperative anemia, p < 0.05. After adjusting for covariates, the results of fully adjusted linear regression revealed that preoperative anemia was significantly associated with LOS (β = 2.04, 95%CI (0.13, 3.96) ), p < 0.05. The results of the subgroup analysis were basically accurate and steady. Regardless of gender, same outcomes were seen when preoperative anemia was defined as a Hb level < 13 g/dL (β = 2.29, 95%CI (0.33, 4.25) ), p < 0.05. In addition, the LOS was shortened with the increase of preoperative hemoglobin (Hb) (β= -0.81, 95%CI (-1.46, -0.1) ), p < 0.05.

CONCLUSION

Preoperative anemia is typical in Chinese patients undergoing radical esophageal cancer resection and is independently associated with prolonged LOS.

Albumin Corrected Anion Gap and the Risk of in-Hospital Mortality in Patients with Acute Pancreatitis: A Retrospective Cohort Study

Purpose

To explore the prognostic value of albumin corrected anion gap (ACAG) within 24 hours of admission to the intensive care unit (ICU) for acute pancreatitis (AP).

Patients and Methods

This was a retrospective cohort study. Adult AP patients admitted to ICU from June 2016 to December 2019 were included in the study, who were divided into three groups according to initial serum ACAG within 24 hours upon ICU admission: ACAG ≤ 14.87 mmol/L, 14.87 < ACAG ≤ 19.03 mmol/L, and ACAG > 19.03 mmol/L. The primary study outcome indicator was in-hospital mortality. Age, sex, Glasgow Coma Scale score, and Acute Physiology and Chronic Health Evaluation II (APACHE II) score were matched through propensity score matching (PSM) method to balance the baseline between the survivors and non-survivors. Multivariate Cox regression was used to determine the relationship between ACAG and in-hospital mortality.

Results

A total of 344 patients (of them 81 non-survivors) were analyzed in this study. Patients with higher ACAG intended to present significantly higher in-hospital mortality, APACHE II score, creatine, lower albumin, and bicarbonate. Multivariate Cox regression analysis after matching demonstrated that white blood cell count, platelet count, and higher ACAG were independently associated with higher in-hospital mortality (ACAG ≤ 14.87 as a reference, 14.87 < ACAG ≤ 19.03 mmol/L with HR of 2.34 and 95% CI of 1.15-4.76, ACAG >19.03 with HR of 3.46 and 95% CI of 1.75-6.84).

Conclusion

Higher ACAG was independently associated with higher in-hospital mortality in patients with AP after matching the baseline between the survivors and non-survivors.