Preoperative Optimization of Diabetic Patients

Overview

Diabetic patients, as part of preoperative evaluation, should have glycated hemoglobin (HbA1C) measured. HbA1C provides information on longterm glucose control. There is a suggestion in the literature that elevated A1C levels predict a higher rate of postoperative adverse events, including infections, myocardial infarction, and mortality. It is unclear whether chronic glycemia, as reflected in raised HbA1C level, is the risk factor for adverse perioperative events or whether it is a surrogate measure for poor perioperative glucose management. Conversely, in a retrospective analysis of 431,480 surgeries perioperative glucose was predictive of increased 30-day mortality, but that HbA1C was a less useful predictor of this measure. In our experience of at the University of Alberta Preadmission Clinic there is significant variability with respect to whether diabetic patients have a valid HbA1C measurement i.e. within 3 months of surgery. If a valid measurement is present, there is also considerable variability with respect to diabetes control.

Purpose: The purpose of this study to retrospectively determine the incidence of diabetes in the surgical population and what proportion of diabetic patients have a valid HbA1C. Hypothesis: A valid (measured within 3 months of surgery) HbA1C measurement is frequently missing prior to surgery and when present has a high chance of being higher than normal. Objectives: Perform a retrospective analysis of all surgeries in Alberta from November 2019 to the present time looking for the following: Primary outcomes: 1. Determine the incidence of diabetes in the surgical population and describe the demographics and clinical charcteristics of patients 2. Determine the incidence of valid HbA1C in diabetic patients presenting for surgery 3. Determine long-term diabetes control through assessment of HbA1C values in diabetic patients presenting for surgery Secondary outcomes: 1. Determine association between HbA1C and post-operative length of stay 2. Determine association between HbA1C and in hospital mortality Design: This study will be a population-based, retrospective observational cohort study. Setting: Alberta Hospitals Participants: Adults with diabetes having surgery in Alberta since November 2019 Descriptive statistics will be tabulated according to HbA1C status and Univariate comparisons of means, medians and proportions will be performed to evaluate the association of independent variables with primary and secondary outcomes. Normally distributed continuous data will be reported as means with standard deviations (SD). Non-normally distributed continuous data will be reported as medians with interquartile ranges (IQR). Categorical variables will be compared using Chi-square test for independence