Glycated hemoglobin A1c level on the day of emergency surgery is a marker of premorbid glycemic control: a retrospective observational study

Abstract Background Current international guideline recommends to maintain blood glucose level ≤ 180 mg/dL in acute ill patients, irrespective of presence of premorbid diabetes. However, there are studies suggested that optimal acute glycemic control should be adjusted according to premorbid glycemic control in patients with chronic hyperglycemia. Accordingly, to obtain the information of premorbid glycemic control would be relevant. However, the HbA1c level on the day of the emergency operation (HbA1c-ope) might not be useful as a surrogate of premorbid chronic glycemic control, since glucose metabolism can be affected by inflammation, severity of illness and surgical invasion. Methods We hypothesized that HbA1c-ope reflects pre-morbid glycemic control. To assess this hypothesis, we conducted a single-center retrospective observational study to assess the association between HbA1c-ope and HbA1c level measured within 30 days before the operation (HbA1c-pre). We screened patients who had been admitted to the ICU of our hospital after emergency surgery during the period from January 2008 to December 2016. Patients in whom both of HbA1c-ope and HbA1c-pre were measured were included in this study. We compared HbA1c-ope and HbA1c-pre using the paired t-test. The correlation between the two HbA1c measurements was assessed using Pearson’s correlation coefficient. Its agreement was assessed using the Bland-Altman approach with 95% confidence intervals. Results We included 48 patients in this study. The mean value of HbA1c-pre was 6.3%, which was not significantly different from the mean value of 6.2% for HbA1c-ope (p = 0.12). There was a significant correlation between HbA1c-pre and HbA1c-ope (r2 = 0.70, p