Abstract
Aims: Although insulin treatment is widely used in critically ill patients with type 2 diabetes mellitus in the intensive care unit (ICU), the clinical outcomes of insulin treatment remain unclear. This retrospective study aimed to explore the impact of insulin treatment on mortality and ICU stay among patients with type 2 diabetes. Methods: We consecutively recruited 578 ICU patients with type 2 diabetes, from 2011 to 2021. According to their medication history regarding insulin use before and after ICU admission, these patients were categorized into three groups: N-N (treated without insulin before and after ICU admission), N-I (treated without insulin before and with insulin after ICU admission) and I-I (treated with insulin before and after ICU admission). Clinical characteristics were analyzed, and clinical outcomes including mortality and the length of ICU stay were compared between the groups. Propensity score matching was performed to obtain comparable subpopulation and the Kaplan-Meier survival curves were graphed to describe the survival trend of different groups. Results: Compared with the N-N group, the N-I and I-I groups had significantly higher ICU mortality rates [20.0% (N-I) and 24.6% (I-I) vs. 0.0% (N-N); p < 0.001; respectively] and longer lengths of ICU stay [ 8.5 (N-I), 9 (I-I) vs. 6 (N-N), p < 0.05, respectively]. After propensity score matching, the N-I group had a significantly higher ICU mortality (15.4% vs. 0.0%, p = 0.025) and poorer survival rates (log-rank p = 0.040) than the N-N group. The length of ICU stay was significantly longer in the I-I group than in the N-N group (10 vs. 7, p = 0.026). Conclusions: Insulin treatment was associated with increased ICU mortality rate and longer length of ICU stay among critically ill patients with type 2 diabetes. Caution is warranted for the regular application of insulin in critical patients with type 2 diabetes.