Diabetes knowledge has little effect on improving outcomes

Jun 3 2005

A new study by Duke Clinical Research Institute researchers finds little relationship between what a diabetic patient knows about the disease and control of its associated cardiovascular risk factors or how well the patient ultimately fares.

The researchers said their analysis indicates that for diabetics, improved disease knowledge alone does not translate into improved blood sugar control, cholesterol levels, weight management or mortality rates. While education may be important, the researchers said that there are likely other health care delivery issues that must be addressed to reduce the risks of diabetic patients dying of heart disease, the main cause of death for diabetic patients.

The results of the Duke analysis were published in the June edition of the American Journal of Cardiology. The study was supported by the American Diabetes Association and the Four Schools Physician-Scientist Training Program, Philadelphia.

"We have long assumed that if we educate patients and make them an active partner in the treatment of their disease, we should be able to dramatically improve their ability to take care of their disease," said Carlos Sanchez, M.D., first author of the paper. Sanchez performed the analysis while a medical student at Duke; he currently is a medical resident at the University of Oregon Health Sciences Center, Portland. "However, in our study, we found no relationship between patients' knowledge of their disease and improvements in the indicators for cardiovascular risk factors.

"We spend so many resources on patient education with the assumption that it will make a difference, but what we seem to be finding is that while education may be a part of the puzzle, it is not adequate by itself," Sanchez continued. "Maybe we should step back and take a closer look at how we are spending our resources. One area that could be improved is better implementation of guidelines for increasing the use of medications we know save lives."

Patients with diabetes are twice as likely as the general population to have acute coronary syndrome (ACS), a condition characterized by blockages in coronary arteries that prevent oxygen-rich blood from nourishing the heart, which can lead to chest pain and possibly heart attack. Additionally, diabetic patients with ACS have twice the death rate as ACS patients without diabetes.

For their study, the team enrolled 200 diabetic patients who were treated at Duke University Hospital for ACS. At enrollment each patient took a standardized test that measured his or her knowledge related to diabetes. The 14-question assessment asked about dietary and life style choices related to glycemic and lipid control, as well knowledge of the effects of the disease on other organ systems. Patients were then ranked as either high-scoring or low-scoring.

Six months later the researchers correlated how each of the groups scored with such clinical measurements as glycemic control, cholesterol levels, body mass index (BMI) and death. The only correlation, not surprisingly, was that diabetes-related knowledge scores increased as years of education increased.

"However, even when we controlled for other potential confounding factors as age, race, insulin requirements, and how long patients had diabetes, we found no correlation between the two groups and measurements of glycemic control, cholesterol levels and BMI," Sanchez said.

Furthermore, in a subset of patients who returned finger-stick blood samples, the team found no difference in measurements of glycemic control. "We found this quite interesting, since these patients had been hospitalized and recovered from a life-altering event, yet there was no difference between the groups in terms of glycemic control."

In terms of mortality, the high-scoring group had a 6-month mortality rate of 6.2 percent, compared to 9.7 percent for the low-scoring group. In terms of heart attacks, 15.5 percent of the high-scoring group suffered at least one, compared to 19.4 percent for the low-scoring group. The differences in both the death and heart attack rates were not statistically significant, the researchers said.

Because of these findings, the researchers said that further studies are needed to determine how best to allocate scarce health care resources to reduce the cardiovascular risk factors facing diabetics.

"Delays in identifying the disease, failure to begin appropriate medications and inadequate dosing are all well-documented shortcomings of our health care system," Sanchez said. He pointed out, for example, that on enrollment to the study, only two-thirds of the patients were taking medications that have been proven in clinical trials to improve the outcomes for diabetics with heart disease. These drugs include aspirin, beta blockers, ACE inhibitors and statins.

Duke cardiologist Kristin Newby, M.D., a senior member of the research team, said that while patient noncompliance, whether because of financial or psychosocial reasons, plays an important role in the under-treatment of heart disease in these patients, physicians' prescription of appropriate medications and the health care delivery system must also play leading roles in improving outcomes.

"These findings indicate that we may need to shift some of our focus in managing diabetes and its complications," said Newby. "Much of the diabetes efforts tend to focus on the microvascular changes caused by the disease: the loss of vision, kidney function or loss of limbs. However, heart disease is the leading cause of death for diabetics.

"Although education and prevention of microvascular complications are important, we need to markedly increase efforts to ensure that health care systems are in place to promote both the delivery of evidence-based care in accordance with existing guidelines and long-term adherence to therapies that are proven to prevent heart attacks and death from heart disease," she said.

Other members of the team include Duke's Vic Hasselblad, Ph.D., Mark Feinglos, M.D., and Mognus Ohman, M.D; and Darren McGuire, M.D., University of Texas Southwestern Medical Center, Dallas. All are members of the Duke Clinical Research Institute.