High HbA1c is associated with decreased 6-month survival and poor outcomes after out-of-hospital cardiac arrest: a retrospective cohort study

Abstract

Background: To evaluate the associations between glycated hemoglobin (HbA1c) at admission and 6-month mortality and outcomes after out-of-hospital cardiac arrest (OHCA) treated by hypothermic targeted temperature management (TTM).Methods: This single-center retrospective cohort study included adult OHCA survivors who underwent hypothermic TTM from December 2011 to December 2019. High HbA1c at admission was defined as a level higher than 6%. Poor neurological outcomes were defined as cerebral performance category scores of 3-5. The primary outcome was 6-month mortality. The secondary outcome was the 6-month neurological outcome. Descriptive statistics, log-rank tests, and multivariable regression modeling were used for data analysis.Results: Of the 302 patients included in the final analysis, 102 patients (33.8%) had HbA1c levels higher than 6%. The high HbA1c group had significantly worse 6-month survival (12.7% vs. 37.5%, p < 0.001) and 6-month outcomes (89.2% vs. 73.0%, p = 0.001) than the non-high HbA1c group. Kaplan-Meier analysis and the log-rank test showed that the survival time was significantly shorter in the patients with HbA1c >6% than in those with HbA1c ≤6%. In the multivariable logistic regression analysis, HbA1c >6% was independently associated with 6-month mortality (OR 5.85, 95% CI 2.26-15.12, p < 0.001) and poor outcomes (OR 4.18, 95% CI 1.41-12.40, p < 0.001).Conclusions: This study showed that HbA1c higher than 6% at admission was associated with increased 6-month mortality and poor outcomes in OHCA survivors treated with hypothermic TTM. Poor long-term glycemic management may have prognostic significance after cardiac arrest.

Glucose control and outcomes in diabetic and nondiabetic patients treated with targeted temperature management after cardiac arrest

“…The relationship between a patient's glucose level and outcomes has been studied in previous studies [19][20][21][22]. Additionally, HbA1c was analyzed in patients treated with TTM after OHCA [34,39]. We classified patients previously diagnosed with diabetes into four groups: those with controlled diabetes, inadequately controlled diabetes, unrecognized diabetes, and no diabetes with adequate glucose control.…”

“…Clinical guidelines generally advocate for an HbA1c threshold of �6.5% for diagnosing diabetes and a range of 5.7 to 6.4% for identifying prediabetes. However, Silverman et al have suggested that in acute-care settings such as emergency departments, an HbA1c of 5.7% is the optimal screening cutoff for prediabetes, while 6% is optimal for diagnosing diabetes [33,34]. Consequently, we established a cutoff value of HbA1c at 6.0% to assess the adequacy of glucose control and diagnose diabetes.…”