Hypoglycemia (Low Blood Sugar) and the Heart

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT01980914
Recruitment Status : Recruiting
First Posted : November 11, 2013
Last Update Posted : January 18, 2018
Information provided by (Responsible Party):
Graydon Meneilly, University of British Columbia

Brief Summary:
The risk of hypoglycemia (low blood sugar) associated with the treatment of diabetes increases with age. Hypoglycemia is a common reason for admission to hospital for older patients with diabetes. Older patients are often unaware that their blood sugar is low and asymptomatic hypoglycemia, as assessed by continuous blood sugar monitoring, is frequent in the elderly. There is also evidence that older people with diabetes are more likely to develop cardiovascular events such a heart attack and more likely to die suddenly when compared to older people without diabetes. It is possible that low blood sugar levels contribute to the increased frequency of these events, but this possibility has never been studied. The purpose of this study is to assess how frequently low blood sugar occurs in older patients with diabetes and to see if low blood sugars adversely affect heart function in these patients.

Condition or disease
Hypoglycemia Type 2 Diabetes

Detailed Description:

Investigators propose a pilot study in 20 patients over age 70 who have type 2 diabetes and are being treated with insulin. These patients will be enrolled from the elderly diabetes clinic at Vancouver General Hospital. Patients will be asked to come to the Gerontology research laboratory in the Research Pavilion at Vancouver General Hospital. A trained research nurse will instrument each patient with an iPro2 glucose sensor (Medtronic Canada). These sensors reliably and continuously measure blood glucose for periods of up to 7 days. Briefly, the skin will be swabbed with a disinfectant and a small catheter will be inserted subcutaneously. This needle will be attached to a glucose sensor. Patients will wear this sensor for 6 days. Patients will measure their glucose using a glucometer 4 times each day during this period and will also be given a log book to keep track of glucose values. Patients will also be asked to record any symptoms of hypoglycemia. At the end of 6 days the sensor will be removed.

At the same time the glucose sensor is started, a trained research nurse will connect the patient to a single use CardioSTAT ECG recorder. The archived ECG waveforms will be downloaded for QT and T-wave alternans analysis. The heart rate and QT interval will be measured at baseline and the end of each interval from the digitized ECG.

Patients and relevant family will be provided with in person education regarding the function and use of the monitor, implications for bathing and sleep, and contact information for troubleshooting. Patients will be asked to change the leads at home twice during the 6 days of the study. Patients will be asked to keep a log book of any cardiac symptoms during the 6 days of the study, as well as their activities. The glucose and CardioSTAT monitor will undergo time synchronization to ensure ability to do correlative analysis.

This is a feasibility pilot to establish preliminary data for analysis. The CardioSTAT monitor will allow assessment of cardiac arrhythmias, myocardial ischemia and cardiovascular autonomic function. The results from the glucose sensor and the CardioSTAT monitor will be correlated and compared to each other to determine if hypoglycemia has an adverse effect on heart function. Hypoglycemia is likely to induce autonomic responses captured on the CardioSTAT monitor and concordant ischemic S-T segment changes if coronary disease is present. It may also detect any resultant arrhythmias, although ischemic arrhythmias are uncommon in 6 days of monitoring. If investigators determine that hypoglycemia has negative effects on cardiac function, investigators may able to design treatments that would prevent these effects from happening in the future.

Study Type : Observational
Estimated Enrollment : 20 participants
Observational Model: Other
Time Perspective: Prospective
Official Title: Impact of Hypoglycemia on Cardiac Function in Elderly Patients With Diabetes
Study Start Date : March 2015
Estimated Primary Completion Date : September 2018
Estimated Study Completion Date : December 2018

Resource links provided by the National Library of Medicine

U.S. FDA Resources

Primary Outcome Measures :
  1. blood sugar measurement [ Time Frame: 6 days ]
    Track hypoglycemia with continuous glucose monitor

Secondary Outcome Measures :
  1. Monitor cardiac function [ Time Frame: 6 days ]
    Track alterations in cardiac rhythm, alterations in cardiovascular autonomic function and myocardial ischemia, collect baseline data to design a subsequent study to assess the effects of various interventions designed to protect the cardiovascular system against hypoglycemia.

Other Outcome Measures:
  1. Correlation [ Time Frame: 6 days ]
    Try to correlate blood sugar (hypoglycemic events) and cardiac function (alterations in cardiac rhythm, alterations in cardiovascular autonomic function and myocardial ischemia).

Information from the National Library of Medicine

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Ages Eligible for Study:   70 Years and older   (Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
These patients will be enrolled from the elderly diabetes clinic at Vancouver General Hospital.

Inclusion Criteria:

  • 70 years old and over
  • had type 2 diabetes for at least 5 years
  • treated with insulin glargine.
  • BMI of between 20 and 35 Kg/M2,
  • A1c between 7 and 8.5 %.
  • well controlled hypertension and hyperlipidemia.

Exclusion Criteria:

  • cannot speak english or give informed consent, or cognitive impairment
  • glomerular filtration rate (GFR) less than 40ml/min,
  • poorly controlled Chronic Heart Failure
  • active coronary artery disease
  • active cerebrovascular disease although a past history of CAD or stroke will not results in exclusion.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01980914

Contact: Boris Feldman 604-875-5115

Canada, British Columbia
Vancouver Coastal Health Research Institute (VCHRI/VCHA) site -Vancouver General Hospital Recruiting
Vancouver, British Columbia, Canada, V6M 1N7
Contact: Boris Feldman    604-875-5115   
Principal Investigator: Graydon S Meneilly, MD         
Sub-Investigator: Kenneth M Madden, MD, MSc         
Sub-Investigator: Andrew D Krahn, MD         
Sponsors and Collaborators
University of British Columbia
Principal Investigator: Graydon S Meneilly, MD University of British Columbia

Responsible Party: Graydon Meneilly, Professor, University of British Columbia Identifier: NCT01980914     History of Changes
Other Study ID Numbers: H13-02734
unfunded ( Other Identifier: UBC )
First Posted: November 11, 2013    Key Record Dates
Last Update Posted: January 18, 2018
Last Verified: January 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Keywords provided by Graydon Meneilly, University of British Columbia:
type 2 diabetes
insulin glargine
cardiac function
myocardial ischemia
cardiac rhythm
autonomic cardiovascular function

Additional relevant MeSH terms:
Diabetes Mellitus, Type 2
Diabetes Mellitus
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases