Association between glycemic variability and 28-day all-cause mortality in patients with ARDS: A retrospective study based on the MIMIC-IV database

Introduction: Despite glycemic variability (GV) being a recognized strong independent predictor of mortality in critically ill patients, its association with the prognosis of patients with acute respiratory distress syndrome (ARDS), a common critical condition in the intensive care unit (ICU), remains poorly understood. The objective of the present study was to evaluate the relationship between GV and all-cause mortality in patients with ARDS. Material and methods In this retrospective study using the Medical Information Mart for Intensive Care IV database version 2.2 (MIMIC IV v2.2), we evaluated the impact of GV on 28-day all-cause mortality among patients with ARDS admitted to ICU. Patients were included based on the new global definition of ARDS within two days of ICU admission. GV was quantified using the Glycemic Coefficient of Variation (Glu _CV ) calculated within the first three days post-admission. Participants were categorized into three tertiles based on their Glu _CV (Low: ≤13.88%, N = 1288; Moderate: 13.88%-22.80%, N = 1291; High: >22.80%, N = 1289). Multivariable Cox proportional hazards models were constructed to analyze the association between Glu _CV and 28-day all-cause mortality in patients with ARDS. Non-linear correlations were explored using restricted cubic splines (RCS). Subgroup analyses were conducted o further investigate the relationship in patient groups defined by age, sex, the severity of ARDS, mean glucose levels with 3 days admission, and history of diabetes. Results A total of 3,868 adult ARDS patients were included in this study. Compared to the Low and Moderate groups, the patients in High Glu _CV group exhibited a higher prevalence of diabetes, more use of insulin and glucocorticoids treatment, and higher levels of mean glucose, CCI, SAPS II and SOFA scores. Multivariable Cox proportional hazards analyses revealed a significant association between Glu _CV and 28-day all-cause mortality in ARDS patients [continuous Glu _CV , HR:1.006, 95% CI: 1.002–1.010; tertiles of Glu _CV , High vs Low Glu _CV , HR:1.21, 95%CI: 1.03–1.43]. Three-knots RCS curve showed that the risk of mortality increased linearly with higher Glu _CV . Subgroup analysis revealed that compared with Low Glu _CV , High Glu _CV was associated with a higher risk of 28-day all-cause mortality in subgroups defined by male, mild severity of ARDS, mean glucose < 140 mg/dl within the first 3 days admission and without a diabetes history. Conclusions Glu _CV is independently associated with increased 28-day all-cause mortality in ARDS patients and could be used as a valuable tool for mortality risk stratification and guiding the treatment strategies of ARDS in the ICU. Further large prospective clinical studies are needed to evaluate the association between Glu _CV and mortality in ARDS patients.