Diabetes affects every a part of the body, from the brain to the feet. High blood sugar, often called diabetes, wreaks havoc on blood vessels. It is sensible that keeping blood sugar under control should prevent diabetes-related damage — but how far to lower blood sugar is an open query.
A study published in today's issue of gave New England Journal of Medicine (NEJM) provides convincing evidence that so-called tight blood sugar control is nice for the guts and circulatory system.
Risks of high blood sugar
Type 2 diabetes is characterised by high blood sugar levels. Over time, high blood sugar damages the small blood vessels throughout the body. This known as microvascular disease. Damage can result in kidney failure, nerve pain, amputations and blindness.
But the leading reason behind complications and death in individuals with diabetes is heart disease, which involves the body's major blood vessels. (This can be called macrovascular disease.) About two-thirds of individuals with diabetes die from heart disease, stroke, or other cardiovascular problems.
An excellent measure of blood sugar is the hemoglobin A1c (HbA1c) test. It shows an individual's average blood sugar level over the past three months. People without diabetes have an HbA1c level of lower than 5.7%. An HbA1c level of 6.5% or higher normally indicates diabetes.
For some individuals with type 2 diabetes, a healthy weight loss program and regular exercise can keep blood sugar under control, but many individuals also need medication. People with diabetes are generally encouraged to take care of tight blood sugar control, which is to scale back HbA1c levels below 7%.
Research has shown that tight blood sugar control can reduce the danger of microvascular complications. But the impact of tight blood sugar control on heart disease has been more complex. latest NEJM Tight blood sugar control also has cardiovascular advantages, the report suggests.
Advantages of strict control
This report is a 10-year follow-up of the Veterans Affairs Diabetes Trial. The trial enrolled 1,791 military veterans with type 2 diabetes with a median age of 60 years. These veterans were randomly assigned to either “intensive” therapy aimed toward bringing blood sugar all the way down to a lower HbA1c goal, or “standard” therapy with the next HbA1c goal. In each group, blood sugar levels were controlled with a mix of oral diabetes medications and insulin injections if needed.
During the five-and-a-half-year trial, the intensive treatment group had a median HbA1c level of 6.9 percent. The average HbA1c level of the usual therapy group was around 8.4%.
More than 1,600 trial participants were followed for one more five years. During that point, the researchers compared what number of participants had a cardiovascular event, akin to a heart attack or stroke, between the intensive therapy and standard therapy groups.
The results were encouraging, each for doctors who've kept blood sugar under tight control and for individuals with diabetes who've worked hard to attain it. The strict control group had a 17 percent lower risk of heart attack and stroke than those with barely higher blood sugar levels. This translates to about 9 fewer heart attacks and strokes per 1,000 people.
Metabolic memory
The study had one other positive result. This reinforced what Dr. Nathan calls “metabolic memory.” As he explains, “the initial period of intervention appears to have lasting effects over time.”
The energetic a part of the VA trial lasted about five and a half years. Subsequently, the Veterans Medical Care Research Study Team was not monitored. Within three years, mean HbA1c levels within the intensive treatment group had trended upward, reducing the difference in levels between the intensive and standard groups from 1.5% to between 0.2% and 0.3%. And yet, the intensive therapy group continued to experience cardiovascular advantages years later.
The effects of intensive treatment don't last eternally, warns Dr. Nathan. At some point, he says, “metabolic memory becomes metabolic amnesia.” But the longer you retain your blood sugar under tight control, the longer the advantages will last.
Balancing Act
Although tight blood sugar control may also help prevent diabetes-related damage, it has some drawbacks. People who aim for tighter control may experience low blood sugar (hypoglycemia), which might be very dangerous. Achieving tight control can be difficult, sometimes requiring multiple medications that may have their very own harmful uncomfortable side effects.
Previous research has shown that folks with long-standing diabetes and heart disease may not profit as much from tighter blood sugar control as individuals with newly diagnosed diabetes. But latest NEJM The report shows that it is rarely too late to regulate blood sugar. The veterans within the trial had poorly controlled diabetes for several years before the study began. And 40% had heart disease after they enrolled within the trial. So not only did intensive treatment reduce the danger of heart disease, it did so in older individuals with long-standing diabetes, lots of whom already had heart disease.
Good blood sugar control is very important for anyone with diabetes. Current guidelines from the American Diabetes Association recommend an HbA1c level of lower than 7%. But the rules also recognize that there isn't any one-size-fits-all rule. If you could have diabetes, ask your doctor if strict blood sugar control is correct for you.