Longitudinal trajectories of blood glucose and 30-day mortality in patients with diabetes mellitus combined with acute myocardial infarction: A retrospective cohort analysis of the MIMIC database

Background Although blood glucose changes have been suggested to be a potential better target for clinical control than baseline blood glucose levels, the association of blood glucose changes with the prognosis in acute myocardial infarction (AMI) patients with diabetes mellitus (DM) is unclear. Herein, this study aimed to investigate association of short-term longitudinal trajectory of blood glucose with 30-day mortality in this population. Methods Data of AMI patients with DM were extracted from the Medical Information Mart for Intensive Care (MIMIC) database in 2003-2019 in this retrospective cohort study. The latent growth mixture modeling (LGMM) model was utilized to classify the 24-hour longitudinal trajectory of blood glucose of the patients. Kaplan-Meier (KM) curve was drawn to show 30-day mortality risk in patients with different trajectory classes. Univariate and multivariate Cox regression analyses were employed to explore the association of longitudinal trajectory of blood glucose within 24 hours after the ICU admission with 30-day mortality. Also, subgroups analysis of age, gender, and AMI types was performed. The evaluation indexes were hazard ratios (HRs) and 95% confidence intervals (CIs). Results Among 1,523 eligible patients, 227 (14.9%) died within 30 days. We identified 4 longitudinal trajectories of blood glucose, including class 1 (a low initial average blood glucose level with steady trend within 24 hours), class 2 (a high initial average blood glucose with gently decreased trend), class 3 (the highest initial average blood glucose with rapidly decreased trend) and class 4 (a high initial average blood glucose level with the trend that increased at first and then decreased). After adjusting for covariates, an average blood glucose level of >= 200 mg/dL was linked to higher risk of 30-day mortality, comparing to that of <140 mg/dL (HR = 1.80, 95%CI: 1.23-2.63). Comparing to patients whose longitudinal trajectory of blood glucose conformed to class 1, those with class 2 (HR = 2.52, 95%CI: 1.79-3.53) or class 4 (HR = 3.53, 95%CI: 2.07-6.03) seemed to have higher risk of 30-day mortality. Additionally, these associations were also significant in aged >= 60 years old, female, male, NSTEMI, and STEMI subgroups (all P<0.05). Conclusion A low level of average blood glucose at the ICU admission or reducing blood glucose to a normal level quickly with adequate measures in 24 hours after ICU admission may be beneficial for AMI patients with DM to reduce the risk of 30-day mortality. These findings may provide some information for further exploration on appropriate range of blood glucose changes in clinical practice.