Tight Blood Sugar Control Helps Diabetics Long-Term
WEDNESDAY, Sept. 10 (HealthDay News) -- Type 2 diabetics who tightly control their blood sugar levels early, even if only for the first 10 years after diagnosis, have reduced risk of heart attack, death and other complications a decade or more later, British researchers report.
The same cannot be said for type 2 diabetics who control their blood pressure for five years after diagnosis, however. The benefits from blood pressure control are only maintained as long as antihypertensive treatment is maintained, the same group of British researchers found.
"It is real encouraging to know that a prolonged period of good [blood sugar] control followed by a prolonged period of mediocre control, can still have good effect on our health," said Dr. Ping H. Wang, professor of medicine and director of the Center for Diabetes Research & Treatment at the University of California, Irvine.
"Humans are not perfect, it is quite often that diabetic patients go through periods of good control and not-so-good control," noted Wang, who was not involved in the studies. "Now, I can go back to my clinic and tell my patients that even though they are not perfect, the good control they have achieved will have long-lasting effect."
Both of the new studies were published in the Sept. 9 online edition of the New England Journal of Medicine. The findings were also expected to be presented Wednesday at the European Association for the Study of Diabetes, in Rome.
The trial, called The United Kingdom Prospective Diabetes Study (UKPDS), "showed continuing benefit of earlier improved glucose control," said lead researcher Rury Holman, a professor of diabetic medicine and director of the Diabetes Trials Unit at the University of Oxford.
For the first study, more than 4,200 patients with type 2 diabetes were randomly assigned to either a restricted diet aimed at improving blood sugar or to intensive blood sugar control with medicines such as insulin or metformin. The patients were followed for an average of about 10 years. Then, for 5 years after the trial ended, patients were asked to check in at clinics annually, but they were no longer mandated to follow any particular blood sugar-lowering treatment.
Holman's team found that, overall, patients who had initially received intensive blood sugar control with metformin during the 10 years of the trial had a 21 percent reduction in microvascular disease, heart attack, and all-cause mortality during the post-trial 5-year period -- when many had adopted less stringent blood sugar control. In fact, these patients reduced their long-term risk of heart attack by 33 percent, the team found. Their overall risk of death was also reduced by 27 percent, compared to patients who had not entered into medicinal blood sugar control during the trial.
"There was no significant change during or after the trial with respect to microvascular disease," Holman added. However, among patients receiving insulin, there was a 24 percent reduction in microvascular disease.
The bottom line: Strict control of blood sugar appears to have healthful effects that last long after such strategies end, the team found.
Would similar results arise for the control of blood pressure? In their second study, Holman's team randomly assigned more than 1,100 type 2 diabetics with high blood pressure to tight or moderate blood pressure control regimens for a four-year period. After that initial phase, the participants were asked to check in with doctors at annual clinics, but no attempt was made by the researchers to maintain each patient's assigned treatment.
The result: Any difference in blood pressure between the two groups (tight or moderate blood pressure control) disappeared two years after the trial ended, and patients lapsed back into less-than-optimum blood pressure control.
"Any diabetes-related endpoint -- such as diabetes-related death or stroke and microvascular disease -- were not maintained following the loss of within-trial blood pressure and antihypertensive therapy differences," Holman said. "No significant changes were seen during or after the trial with respect to [heart attack] or all-cause mortality," he said.
This leads Holman to believe that control of blood sugar, rather than blood pressure, may be the most effective way to help diabetics over the long-term, in terms of reducing diabetes-linked complications.
"The full benefit of blood pressure lowering was achieved during the trial, but for glucose, the benefits persisted and increased with time in the intensively treated group, even though glucose levels no longer differed with respect to the conventional group," Holman said. "This suggests that early glucose-lowering treatment brings greater benefits than starting later in the course of the disease, reducing not only micro but also macrovascular risks."
"Both blood sugar and blood pressure are important for diabetic complications, including heart diseases," he stressed. "However, the effect of blood sugar and blood pressure behave differently. Blood sugar [control] has a long-lasting effect, even after 10 years."
For more on diabetes, visit the American Diabetes Association.