Clinical trial NCT03109951
Conditions: Type 2 Diabetes Mellitus Colonoscopy
Keywords: Type 2 diabetes colonoscopy hypoglycemia hyperglycemia polyethylene glycol
Sponsor: Catholic Kwandong University
Start date: 2017-03-25; Completion date: 2019-12-31
Enrollment: 187 participants; Allocation: NA; Intervention model: SINGLE_GROUP

Brief summary:
Type 2 diabetes is rapidly increasing globally and has been associated with an increased risk of colorectal cancer. Therefore, the numbers of diabetic patients who will undergo colonoscopic screening are expected to grow exponentially. Colonoscopic preparation entails prolonged fasting, cessation of anti-diabetic medication and ingestion of preparation medications. This may put the diabetic patient at risk of potentially dangerous hypo- or hyperglycemia. However, studies regarding the safety of colonoscopic preparation in diabetic are lacking. In this study, the investigators aim to discover the prevalence of abnormal glucose levels in diabetic patients who undergo colonoscopy. The investigators also aim to find out risk factors for abnormal glucose levels and develop a safe preparation protocol.

Detailed description:
1. Type 2 diabetes subjects who will undergo colonoscopy will be prospectively enrolled when visiting the outpatient clinic.
2. Subjects will be instructed to fast from 6pm of the day before colonoscopy.
3. Subjects will be instructed to abstain from diabetes medication while the subjects fast.
4. Subjects who are scheduled to undergo colonoscopy in the morning will take colonoscopy preparation medication (2L (liter) of polyethylene glycol with ascorbic acid) in a split dose (i.e. 1L from 8-10 pm of the day before colonoscopy and 1L 4-6 hours before colonoscopy). Those who will undergo colonoscopy in the afternoon will take 2L of the preparation medication 6 hours before colonoscopy.
5. Subjects will be instructed to take the preparation medication at rate of 250 mL every 10 to 15 minutes.
6. Upon arrival at the endoscopy center of International St. Mary's hospital, subjects will be given a self-administered questionnaire which will ask about their age, gender, duration of diabetes, type of diabetes medication, time of last diabetes medication taken, knowledge of hypo/hyperglycemia symptoms, previous hypo/hyperglycemia experience, self-treatment of hypoglycemia (if done), total amount of colonoscopy preparation medication ingested, total fasting time and time of last preparation medication ingested.
7. Subjects will have vital signs (blood pressure, heart rate) taken and their capillary glucose levels checked using the Accu-Chek Performa.
8. Any subjects with capillary glucose levels \<70mg/dL or \>250mg/dL will be reported to the attending physician. Those with an initial glucose level \<70mg/dL will be given a piece of candy and have their glucose rechecked in 10 mins. Subjects will be asked if the hypoglycemic symptoms (if any) have abated. Those with a glucose level \>250mg/dL will undergo hydration with normal saline at 120 ml/Hr. Those who do not respond to treatment or are in critical condition will be moved to the Emergency department for treatment. Subjects who respond to treatment will have their glucose levels checked after colonoscopy before undergoing discharge. Those with abnormal levels upon follow-up testing will be sent to either the endocrinology outpatient clinic or the emergency room depending on their clinical severity.
9. All data will be recorded by initials with patient identities masked. All data will be kept in a locked and secure location by the principal investigator.

Arms: arm 1: Type 2 diabetes patients undergoing colonoscopy with preparation with 2L of polyethylene glycol.
Interventions: intervention 1: Colonoscopy preparation using polyethylene glycol
Intervention descriptions: intervention 1: Colonoscopy preparation using standard preparation with 2L of polyethylene glycol.

Protocol documents:
Prot_SAP_000.pdf: 
Study title: Abnormal blood sugar tests in diabetic patients during 
colonoscopy preparation  
 
Primary Investigator: Myong Ki Baeg, MD, PhD 
Investigation site: International St. Mary’s Hospital, Catholic Kwandong University 
 
Last modified: Feb 2, 2018 
 
 
 


 
Objectives 
1. Primary: To discover the incidence of abnormal glucose levels after fasting and bowel preparation 
for colonoscopy in type 2 diabetes subjects.  
2. Secondary  
① Find out the risk factors for abnormal glucose levels 
② Find out if self-treatment is sufficient to treat hypoglycemia which occurs during fasting and 
bowel preparation.              
Background 
Diabetes is rapidly increasing, with about 11% (5.5 million) of the Korean population expected to be 
diabetic in 2030. Diabetes is a known risk factor for colorectal cancer and diabetes patients are 
recommended to undergo routine colonoscopic surveillance. Colonoscopy requires fasting and bowel 
preparation, however, their effects on glucose levels have not been investigated.  
Subjects normally undergo 14-20 hours of fasting before colonoscopy. In diabetes patients, 14-17 
hours of fasting reduces plasma glucose by 20-40%, which increases the risk of hypoglycemia. 
Furthermore, subjects are instructed to forgo taking antidiabetic medications during fasting, which 
may induce hyperglycemic crisis or abnormal glucose levels due to Dawn phenomenon or Somogyi 
effect. Dehydration during bowel preparation may also increase the risk of abnormal glucose levels. In 
diabetic patients, autonomic dysfunction may reduce recognition of hypoglycemic symptoms, 
increasing risk of catastrophic events.  
In diabetic patients who underwent ophthalmologic procedures after 8 hours of fasting, hypoglycemia 
has been reported in 3% and hyperglycemia in 2.4%. One study which investigated abnormal glucose 
responses in diabetes patients who underwent colonoscopy found a hypoglycemic rate of 20%. 
Therefore, we aim to investigate the occurrence of abnormal blood glucose levels in diabetes patients 
during colonoscopy preparation.  
 


Subjects 
1. Inclusion criteria: Type 2 diabetes subjects between the ages of 20-75 who have colonoscopy 
performed at the endoscopy center of International St. Mary’s Hospital.  
2. Exclusion criteria 
① Type I diabetes patients 
② Those who have not completed colonoscopy preparation 
③ Those who have not met the fasting requirements 
④ Patients with known ongoing infection 
⑤ Patients with known cancer, undergoing current treatment 
 
Subject numbers 
The incidence of abnormal glucose levels is expected to be between 5 to 10%. 50 positive subjects 
are required for multivariable analysis, therefore 1000 subjects should be included in this study.  
 
Study design 
1. Colonoscopy preparation 
① Subjects will be instructed to fast from 6pm of the day before colonoscopy. 
② Subjects will be instructed to abstain from diabetes medication while the subjects fast. 
③ Subjects who are scheduled to undergo colonoscopy in the morning will take colonoscopy 
preparation medication (2L (liter) of polyethylene glycol with ascorbic acid) in a split dose (i.e. 
1L from 8-10 pm of the day before colonoscopy and 1L 4-6 hours before colonoscopy). 
Those who will undergo colonoscopy in the afternoon will take 2L of the preparation 
medication 6 hours before colonoscopy. 


④ Subjects will be instructed to take the preparation medication at rate of 250 mL every 10 to 
15 minutes. 
2. Confirmation of diabetes 
① Diabetes history will be rechecked by a trained nurse who is blind to the study at the 
preparation room of the endoscopy center.  
② Subjects will fill out a questionnaire and have their plasma glucose checked while awaiting 
colonoscopy.  
3. Treatment of abnormal glucose levels 
① Hypoglycemic patients with a glucose level < 70mg/dL will be given 5% dextrose water.  
② Hyperglycemic patients with a glucose level > 250mg/dL will be given normal saline.  
③ Treated subjects with be discharged after confirmation of glucose level restoration to 
normal values.  
 
Study variables 
1. Age, gender 
2. Amount and total time of colonoscopy preparation. Total fasting time. Time from last antidiabetic 
medication taken to colonoscopy.  
3. Diabetes history (years), Diabetes treatment method (exercise/diet, oral medication, methods 
including insulin), other injected agents, previous history of hypo/hyperglycemia, hypoglycemia 
awareness 
4. Plasma glucose level before colonoscopy 
 
Statistical Analysis 


Primary endpoint: Percentage of study subjects with hypo or hyperglycemia 
Secondary endpoint 
① Risk factors of hypo/hyperglycemia 
② Effect of hypoglycemia self-treatment 
Verify the risk factors using T test the X2 test.  
Identify the odds ratios of risk factors by univariable and multivariable analysis.  
 
References 
Mary Ann Vann, Perioperative management of ambulatory surgical patients with diabetes mellitus, 
Current Opinion in Anaesthesiology, 2009; 22: 718-724 
Kollarits et al, Perioperative treatment of patients with diabetes having eye surgery with local 
anesthesia in an ambulatory facility, Ophthalmic Surgery Lasers Imaging, 2004; 35: 185-188 
Joshi et al, Society for Ambulatory Anesthesia Consensus Statement on Perioperative Blood 
Glucose Management in Diabetic Patients Undergoing Ambulatory Surgery, Anesthesia Analgesia, 
2010’ 111: 1378-1387 
Yao et al, Enteral nutrition before bowel preparation improves the safety of colonoscopy in the 
elderly, The Turkish Journal of Gastroenterology, 2013; 24: 400-405 

ICF_001.pdf: 
INFORMED CONSENT FORM 
Last modified: February 2nd, 2018 
 
1. Study title:  
Abnormal Blood Sugar Tests in Diabetic Patients During Colonoscopy 
Preparation 
 
2. Principal Investigator: Myong Ki Baeg, MD, PhD, Department of Gastroenterology, International 
St. Mary’s Hospital, Incheon, Republic of Korea 
 
3. What you should know before agreeing to study participation 
We will comply with legal regulations and the Declaration of Helsinki ethics principles. The study 
will be fully explained to you before signing the study consent form. You may inquire about this 
study and the informed consent form at anytime. You may decide to participate or not participate 
in this study of your own free will.. Please take you time before deciding on participation. You 
may consult with your kin or others before making a decision. There are no repercussions to 
whichever decision you may make. Your data will be blinded before undergoing analysis, 
rendering it anonymous.  
 
4. Study goal: To discover the incidence of abnormal glucose levels after fasting and bowel 
preparation for colonoscopy in type 2 diabetes subjects. 
 
5. Study time: From colonoscopy preparation to exiting the endoscopy department. Expected to 
end on December 31st, 2019.  
 
6. How may are expected to enroll in this study: From 1000 to 2000 subjects.  
 
7. How is the study done? 
This informed consent form will be explained to you at the outpatient clinic of the International St. 
Mary’s hospital. If you agree, guidelines about colonoscopy preparation will be explained to you 


before colonoscopy. If you have hypoglycemic symptoms during fasting or preparation, please use 
self-remedies such as candy or juice. If these do not relieve your symptoms, please contact or 
come to a nearby medical facility or the International St. Mary’s hospital. After colonoscopy 
preparation, when you enter the preparation unit of the endoscopy center, you will have your 
blood sugar checked and be instructed to fill out a questionnaire. If you have hypo or 
hyperglycemia, you will be treated for this condition.  
 
8. What must I conform to during the study? 
Please conform to the colonoscopy fasting and preparation medication instructions. Otherwise, 
there is nothing that you must do.  
 
9. What discomfort and risks do I undergo by participating in this study? 
Fasting and preparation for colonoscopy are done regardless of study participation. Therefore, 
there are no added risks by enrolling in this study. When we check your blood sugar, there will be 
a little pinprick.  
 
10. Are there any benefits to participating in this study? 
There are no added benefits by participating in this study.  
 
11. What should I do if I don’t want to participate in this study? 
There are no penalties and the colonoscopy will be done as scheduled.  
 
12. Is there any reimbursement for injuries/harm inflicted during this study? 
This study will not cause any additional injuries or harm. Therefore, there will be no 
reimbursement for any injuries or harm which occur during colonoscopy or colonoscopy 
preparation.  
 
13. What about dropping out from the study? 
You may request to drop out from the study at any time. Please contact the study investigator or 


the IRB whenever you want to drop out from the study.  
 
14. Who do I contact? 
The institutional review board of International St. Mary’s Hospital 032-290-2617 
Email: hkchoi@ish.ac.kr  
 
 


Informed consent 
I have been thoroughly informed about this study and all questions that I may have about this 
study have been answered. I enter this study of my own free will and confirm that I will have a 
copy of this consent form given to me after signing. 
 
Participant 
Name                          Signature                           Date                    
 
Legal guardian (if needed) 
Name                          Signature                           Date                      
 
Investigator 
Name                          Signature                           Date