Elevated blood glucose is one of the hallmarks of diabetes — especially uncontrolled diabetes — and blood glucose control is one of the key areas of diabetes management. But diabetes isn’t the only condition that can cause elevated blood glucose, at least in the short term.
A recent study focuses on elevated blood glucose in people admitted to a hospital for a heart attack. It included both people with diabetes and those without it, looking at the effect of blood glucose on outcomes like survival and the likelihood of experiencing further cardiovascular events. Perhaps surprisingly, the effect of blood glucose on these outcomes was most pronounced in people without diabetes.
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High glucose at admission predicts worse outcomes
For the study, published in the Journal of Diabetes Investigation, researchers looked at 1,288 people who had heart attacks and were admitted to 11 different hospitals in Chengdu, China, between March 2014 and June 2019. These patients were divided into several different groups: those with and without diabetes, and those with and without high blood glucose within each diabetes-status group. The cutoff for high or not-high blood glucose was decided after the fact, based on how well it predicted survival during the study’s follow-up period.
The main end points the researchers were interested in were death from all causes, and major cardiovascular events like another heart attack or a stroke. During the study’s 15-month follow-up period, 210 people in the study group died, six experienced another non-fatal heart attack, and 34 experienced a non-fatal stroke. Based on these results, the researchers found that a blood glucose level cutoff of 266 mg/dl — at the time of hospital admission for the original heart attack — was most predictive of the risk of dying during the follow-up period for people with diabetes. In other words, people with a glucose level above this cutoff were more likely to die during the next 15 months, and those with a glucose level below this cutoff were less likely to die.
For people without diabetes, the most predictive blood glucose level cutoff for dying within 15 months was 122 mg/dl, at the time of hospital admission for their heart attack. Having a blood glucose level above this cutoff was found to independently predict the risk of death — something that couldn’t be said for people with diabetes, where the relationship between blood glucose levels and death within 15 months was weaker.
What do the numbers mean?
It goes without saying that better blood glucose control has health benefits regardless of whether you have a heart attack. But up to this point in time, there have been conflicting messages from studies about how an elevated blood glucose level at the time of a heart attack predicts health outcomes, including the risk of death. Some studies have used a cutoff level for high blood glucose that isn’t based on heart attack-related outcomes, and some haven’t distinguished between people with and without diabetes.
So the goal of the new study was to shed some light on the differences between people with and without diabetes, and to figure out how high someone’s blood glucose had to be to meaningfully predict a person’s risk of dying following a heart attack. On both of these counts, the new study provided valuable information.
Based on the new research, two things are clear. People with diabetes can’t be treated the same as those without diabetes when it comes to predicting their risk of death following a heart attack, based on their blood glucose level at the time of admission. And blood glucose levels more strongly predict this risk in people without diabetes than in people with diabetes.
More studies are needed on how glucose levels affect heart attack outcomes in people with diabetes, the researchers note. But based on this study, they write, it makes sense to follow a more active treatment and follow-up strategy for people without diabetes who have a blood glucose level above 122 mg/dl at the time of hospital admission, than for those those with a lower glucose level.
Want to learn more about protecting your heart? Read “Does Diabetes Hurt Your Heart?” “Fight Off Heart Disease With These Five Heart-Healthy Foods” and “Lower Your Risk of Heart Disease.”