Hypoglycemia (Low Blood Sugar) and the Heart
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.
Type 2 Diabetes
|Study Design:||Time Perspective: Prospective|
|Official Title:||Impact of Hypoglycemia on Cardiac Function in Elderly Patients With Diabetes|
- blood sugar measurement [ Time Frame: 6 days ] [ Designated as safety issue: No ]Track hypoglycemia with continuous glucose monitor
- Monitor cardiac function [ Time Frame: 6 days ] [ Designated as safety issue: No ]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.
- Correlation [ Time Frame: 6 days ] [ Designated as safety issue: No ]Try to correlate blood sugar (hypoglycemic events) and cardiac function (alterations in cardiac rhythm, alterations in cardiovascular autonomic function and myocardial ischemia).
|Study Start Date:||February 2014|
|Estimated Study Completion Date:||January 2015|
|Estimated Primary Completion Date:||December 2014 (Final data collection date for primary outcome measure)|
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 ipro 2 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 continuous ambulatory 12-lead ECG cardiac monitor (48 hour Holter monitor). The archived 12-lead 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 12-lead 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 have to return to the laboratory every 2 days to have the Holter monitor and the ECG leads replaced. 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 Holter monitor will undergo time synchronization to ensure ability to do correlative analysis.
This is a feasibility pilot to establish preliminary data for analysis. The Holter monitor will allow assessment of cardiac arrhythmias, myocardial ischemia and cardiovascular autonomic function. The results from the glucose sensor and the Holter 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 Holter 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.
|Canada, British Columbia|
|Vancouver Coastal Health Research Institute (VCHRI/VCHA) site -Vancouver General Hospital||Not yet recruiting|
|Vancouver, British Columbia, Canada, V6M 1N7|
|Contact: Chris K Lockhart, BSc 604-875-4111 ext 68535 Chris.Lockhart@vch.ca|
|Principal Investigator: Graydon S Meneilly, MD|
|Sub-Investigator: Kenneth M Madden, MD, MSc|
|Sub-Investigator: Andrew D Krahn, MD|
|Principal Investigator:||Graydon S Meneilly, MD||University of British Columbia|