Retrospective Review of Preoperative Optimization of Diabetic Patients
Conditions: Diabetes, Surgery Related Complications Rate
Sponsor: University of Alberta

Dr. Dillane “Preoperative Optimization of Diabetic Patients”                                                             
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Retrospective Review of Preoperative Optimization of Diabetic Patients  
 
Derek Dillane  
Chair Anesthesiology & Pain Medicine  
Tel: (780) 407-1303 
2-150 Clinical Sciences Building 
11304 - 83 Ave NW 
Edmonton, AB, T6G 2G3 
dillane@ualberta.ca 
Maha Alsaif 
Department of Anesthesiology and Pain Medicine  
University of Alberta 
Fadi Hammal 
Department of Anesthesiology and Pain Medicine  
University of Alberta 
Rodger Craig 
Department of Anesthesiology and Pain Medicine  
University of Alberta 
 
 
 
 
 
 
 
 
 
 
 
 

Dr. Dillane “Preoperative Optimization of Diabetic Patients”                                                             
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Table of Contents 
1. 
Title page: ................................................................................................................................ 3 
1.1. Title: ............................................................................................................................... 3 
1.2. Principal investigator:..................................................................................................... 3 
1.3. Sponsor: .......................................................................................................................... 3 
1.4. Study Site: ...................................................................................................................... 3 
2. 
List of Abbreviation: ................................................................................................................ 4 
3. 
Summary .................................................................................................................................. 5 
3.1. Rationale:........................................................................................................................ 5 
3.2. Objectives: ...................................................................................................................... 5 
4. 
Methods: .................................................................................................................................. 6 
4.1. Design, setting and population: ...................................................................................... 6 
4.2. Inclusion criteria: ............................................................................................................ 6 
4.3. Data collection:............................................................................................................... 6 
4.4. Data Sources: .................................................................................................................. 7 
4.5. Data Analysis: ................................................................................................................ 7 
5. 
Ethics Considerations: ............................................................................................................. 8 
6. 
References:............................................................................................................................... 9 
 
 
 
 
 
 

Dr. Dillane “Preoperative Optimization of Diabetic Patients”                                                             
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1. Title page:  
1.1. Title: 
Full Title: Retrospective Review of Preoperative Optimization of Diabetic Patients  
 
Short Title: Preoperative Optimization of Diabetic Patients 
1.2. Principal investigator:  
⁃ Derek Dillane  
Associate Professor  
Chair, Faculty of Medicine & Dentistry - Anesthesiology & Pain Medicine  
Tel: (780) 407-1303 
2-150 Clinical Sciences Building 
11304 - 83 Ave NW 
Edmonton, AB, T6G 2G3 
dillane@ualberta.ca 
 
1.3. Sponsor:  
Faculty of Medicine & Dentistry – Department of Anesthesiology & Pain Medicine 
 
1.4. Study Site:  
University of Alberta Hospital  
 
 
 
 
 
 
 
 
 

Dr. Dillane “Preoperative Optimization of Diabetic Patients”                                                             
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2. List of Abbreviation:  
 
DM: Diabetes mellitus 
HbA1C: Glycated hemoglobin 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Dr. Dillane “Preoperative Optimization of Diabetic Patients”                                                             
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3. Summary  
3.1. Rationale:   
Intraoperative and postoperative hyperglycemia is associated with worse patient outcomes, 
including increased infections and greater mortality. There are important quality improvement 
gaps in perioperative glycemic management in Alberta – data shows that 1 in 5 patients with 
diabetes has no glucose measurements on the day of their surgery and two-thirds will have 
hyperglycemia (defined as a glucose more than 10 mmol/L). 
Diabetic patients, as part of preoperative evaluation, should have glycated hemoglobin (HbA1C) 
measured. HbA1C provides information on long-term 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 [1-3]. 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 van den Boom et al found that perioperative glucose was predictive 
of increased 30-day mortality, but that HbA1C was a less useful predictor of this measure [4]. In 
our experience of at the University of Alberta Pre-admission 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. 
 
3.2. 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 
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 

Dr. Dillane “Preoperative Optimization of Diabetic Patients”                                                             
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4. Methods: 
4.1.  Design, setting and population: 
This is a population-based, retrospective observational cohort study of diabetic patients 
undergoing surgery in all hospitals in Alberta.  
Participants:  Adults with diabetes having surgery in Alberta since November 2019  
 
4.2. Inclusion criteria: 
- 
Age 18 or greater 
- 
Having any surgical procedure at any hospital in Alberta  
- 
Having a diagnosis of diabetes or prediabetes at any stage preoperatively 
 
4.3. Data collection:  
The following data will be collected:  
Age 
Gender 
Weight  
Height 
Type of surgery 
Day surgery or in-patient 
Diabetes medications 
Medications 
Medical history 
Pre-operative blood glucose measured on day of surgery: yes/no 
Pre-operative glucose value if yes to previous 
Intra-operative blood glucose measured on day of surgery: yes/no 
Intra-operative blood glucose value if yes to previous: average/highest value 
Post-operative blood glucose measured on day of surgery: yes/no 
Post-operative blood glucose value if yes to previous 
Average and highest day of surgery blood glucose value 
Length of hospital stay 
In hospital mortality 

Dr. Dillane “Preoperative Optimization of Diabetic Patients”                                                             
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Complications 
HbA1C measurements on record: yes/no 
Valid HbA1C (within 3 months of surgery) measurements on record: yes/no  
Period of time between HbA1C measurement and surgery date 
Values of all HbA1C measurements  
 
The study dataset will be encrypted and password protected, and stored on secure servers at the 
University of Alberta that can only be accessed through a password protected computer. 
 
4.4. Data Sources: 
Data sources will include eCritical Alberta/TRACER and Connect Care/Enterprise data 
repositories, AHS Data Integration, Management and Reporting (DIMR) administrative 
databases. Provlab, DAD, DOSE, SCM, Vital Statistics, and Provincial Registry. 
Data from eCritical/TRACER and Connect Care/Enterprise provide demographic, diagnostic, 
and laboratory data.  
DIMR provides data elements on health care utilization in Alberta including: 
admission/discharge/transfers, vital statistics, costing, billing and claims, laboratory, and 
ambulatory care.  Provlab for lab results; DAD, DOSE, SCM for medication use; and Vital 
Statistics and Provincial Registry for mortality. 
Data will be received directly from the data custodian via secure electronic transfer. Prior to 
transferring the data, the data custodian will replace personal identifiers with unique record 
numbers. A key linking the identifiers with the unique record numbers will be stored by the data 
custodian. Linking of data between sources will be performed by AHS analysts prior to receipt of 
data by the investigators. 
 
4.5. Data Analysis: 
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 

Dr. Dillane “Preoperative Optimization of Diabetic Patients”                                                             
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using Chi-square test for independence. Generalized linear regression models using stepwise 
variable selection (with default enter and stay criterion) will be used. A p-value <0.05 will be 
considered significant for all statistical tests.  
 
5. Ethics Considerations: 
This study will be a retrospective evaluation of prospectively collected data and does not require 
any direct patient contact. All data will be de-identified prior to being obtained by the study team 
and prior to analysis. All data will be housed in encrypted files stored on a secure server at the 
University of Alberta. Data will only be accessed through password-protected computers. 
Waiver of consent will be sought. 
 
 
 
 

Dr. Dillane “Preoperative Optimization of Diabetic Patients”                                                             
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6. References: 
1. 
Dronge, A.S., et al., Long-term glycemic control and postoperative infectious 
complications. Arch Surg, 2006. 141(4): p. 375-80; discussion 380. 
2. 
Jones, C.E., et al., Association Between Preoperative Hemoglobin A1c Levels, 
Postoperative Hyperglycemia, and Readmissions Following Gastrointestinal Surgery. 
JAMA Surg, 2017. 152(11): p. 1031-1038. 
3. 
Stryker, L.S., et al., Elevated postoperative blood glucose and preoperative hemoglobin 
A1C are associated with increased wound complications following total joint 
arthroplasty. J Bone Joint Surg Am, 2013. 95(9): p. 808-14, S1-2. 
4. 
van den Boom, W., et al., Effect of A1C and Glucose on Postoperative Mortality in 
Noncardiac and Cardiac Surgeries. Diabetes Care, 2018. 41(4): p. 782-788.