Euglycaemic diabetic ketoacidosis and its risk factors in patients undergoing coronary artery bypass grafting surgery: a single-centre nested case-control study in China

Abstract

Objectives: This study examines the incidence and risk factors of euglycaemic diabetic ketoacidosis (euDKA) in patients undergoing coronary artery bypass grafting (CABG) and evaluates their postoperative outcomes over a 6-month follow-up period.

Design: This study is a single-centre, nested case-control study, conducted in Tianjin, China.

Setting: An international cardiovascular hospital.

Participants: A total of 1524 patients, with a mean age of 64 (9) years, who underwent isolated elective CABG surgery were reviewed.

Primary and secondary outcome measures: Data were extracted from electronic medical records. EuDKA cases were identified by reviewing laboratory examination results until discharge, including arterial blood gas analysis and urine samples. Logistic regression analysis was used in a case-control design to identify potential risk factors of sodium-glucose cotransporter 2 inhibitor (SGLT2i)-associated euDKA. Post-discharge follow-up was conducted through regular outpatient visits.

Results: 15 patients with euDKA, all with type 2 diabetes, were identified post-surgery, 13 of whom were SGLT2i users. The cumulative incidence of euDKA within 7 days after surgery was 1% in the cohort, increasing to 7.6% among those who discontinued SGLT2i 1-6 days (n=171) before surgery. A case-control study added seven additional confirmed euDKA patients to the case group, resulting in 20 cases and 95 controls. Univariate regression analysis revealed that the risk of euDKA was 7.304 times higher (95% CI 2.517 to 21.197; p<0.001) for patients who took their last dose within 3 days prior to surgery compared with patients who discontinued SGLT2i 3-6 days before surgery. During the intraoperative period, pH <7.35 (OR: 7.017, 95% CI 1.849 to 26.638; p=0.004) and blood glucose <10 mmol L^-1 (OR: 6.882, 95% CI 1.822 to 25.997; p=0.004) were associated with a higher risk of euDKA. Compared with controls, euDKA patients experienced a higher rate of type 5 myocardial infarction (6/20 (30%) vs 9/95 (9.5%); p=0.035) and recurrent ketosis post-discharge (3/19 (15.8%) vs 0/87 (0%); p=0.005).

Conclusions: This cohort study highlights a notable incidence of euDKA following CABG, particularly among patients using SGLT2i. Close monitoring in the ICU is recommended for patients with intraoperative abnormal blood glucose and pH levels to prevent euDKA.

Keywords: Adult intensive & critical care; Cardiac surgery; Case-Control Studies; Diabetes Mellitus, Type 2; EPIDEMIOLOGIC STUDIES; Risk Factors.

Figure 1. Flowchart of the participants in the study. DKA, diabetic ketoacidosis; EuDKA, euglycaemic diabetic ketoacidosis; SGLT2i, sodium-glucose cotransporter 2 inhibitors; T2D, type 2 diabetes.

Figure 2. Cumulative incidence of EuDKA after CABG. CABG, coronary artery bypass grafting; CI, cumulative incidence; EuDKA, euglycaemic diabetic ketoacidosis; POD, postoperative day; Pre-op, preoperation; SGLT2i, sodium-glucose cotransporter 2 inhibitors.

Figure 3. Characteristics and ORs with 95% CIs for various factors associated with SGLT2i-related euDKA at different stages of surgery. *The significance threshold in multiple regression model was adjusted using Bonferroni correction (α=0.017, calculated as 0.05/3). Bold font indicates statistical significance at p<0.017 in model 1. **The significance threshold in multiple regression model was adjusted using Bonferroni correction (α=0.013, calculated as 0.05/4). Bold font indicates statistical significance at p<0.013 in model 2 and model 3. EuDKA, euglycaemic diabetic ketoacidosis; N/A, not applicable; SGLT2i, sodium-glucose cotransporter 2 inhibitors.