(December 2, 2008 - Insidermedicine) On a recent trip to Atlanta we caught up with Dr. Venkat Narayan (MD, MSc, MBA) who is the Hubert Professor of Global Health & Epidemiology at Rollins School of Public Health, Emory University. His research centers on public health aspects of diabetes and chronic diseases. Until recently he led the Diabetes Epidemiology and Statistics Branch at the Centers for Disease Control, prior to which he was also a visiting scientist at the National Institutes of Health.
What is diabetes?
Diabetes, essentially is a metabolic condition which is characterized by high levels of glucose, so for example if you had your glucose measured when you were fasting and it was greater than 126mg/dl, you have diabetes. Another way of diagnosing diabetes is to have what’s called a glucose tolerance test, in which you are given a volume of glucose to drink and a measurement is taken after 2 hours, and if the measurement is greater than 200mg/dl, that is also considered to be diabetes. Essentially diabetes is a metabolic condition which also has abnormalities in blood pressure, lipids, et cetera, it is not just glucose.
Pre-diabetes is a condition which puts a person at high risk of diabetes; your fasting glucose of between 100 and 125mg/dl, and your two hour glucose of between 140 and 200mg/dl. Again, you don’t have diabetes, but you’re at high risk of developing diabetes. The pre-diabetic group is a group where we target prevention.
What diagnositc tests are available?
Essentially the policy today is if you are at high risk of developing diabetes, when you go to your doctor for a regular checkup, you should get your glucose checked, ideally a fasting glucose test would be the easiest thing to do since it is just one blood draw, and if that is high they can repeat it to confirm it. There are other tests (eg capillary glucose) but they are not as good as the fasting glucose test.
How can diabetes be treated and prevented?
Preventing diabetes in people with pre-diabetes is quite different from treating people who already have diabetes. If somebody is at high risk, they should go to their doctor and have a blood glucose done, and if they are found to have pre-diabetes, what we recommend as the primary treatment would be an aggressive lifestyle intervention; there is solid evidence to support this. Essentially what we mean is getting a person to, firstly, do about 30 minutes of physical activity per day (this can be brisk walking), secondly, to try and lose weight, about 5-7% of their weight if they are overweight (eg a 200lb person would lose between 10-14lbs of weight), and thirdly, to modify their diet by lowering both portion size, lowering amount of fat in the diet, and also increasing the fiber in the diet. This would be the initial strategy and it is often helped by having counselors and social support groups to help achieve these goals, and by monitoring progress. In selected people who, for example, have very high levels of fasting glucose, and also have high levels of 2-hour glucose, there may be a role for adding the drug Metformin, but I would like to emphasize that the primary way of preventing diabetes is lifestyle modification, and it has huge benefits in preventing progression to diabetes by about 50% or higher.
Once a person is diagnosed to have diabetes, which is a 2-hour glucose of 200mg/dl or over, or a fasting glucose of 126mg/dl and over, then it is a different situation, and the current recommendation is to again start on lifestyle intervention, but the person may require Metformin, and beyond that blood glucose control may need to be tailored to the individual; at some point they may need another drug, or at some point in life they may need insulin. We manage that based on glucose levels. But it also presents the opportunity of managing other risk factors for cardiovascular disease which is a major cause of morbidity and death among people with diabetes. A person with diabetes would need to attend to their glucose levels but also for blood pressure control, controlling their lipids, which is high cholesterol levels, taking Aspirin which can prevent a lot of vascular complications, and there may be a role for regularly examining the eyes to prevent these complications from arising.
If I had pre-diabetes…
If I had pre-diabetes, given the knowledge we have about the condition, I would be very optimistic about preventing diabetes. Clearly, evidence suggests that if I could change my lifestyle, do simple things like 30 minutes of physical activity per day, modify my diet, and try and lose between 5 & 7% of my body weight, then I can prevent going on to get diabetes by 50%, which is a major gain. This is achievable. Lifestyle intervention is far more effective than any drug in the field, and we’ve also found from studies that even if you have genes for diabetes, lifestyle intervention can eliminate your risk very substantially, so it is something that I would take very seriously.
So if I had pre-diabetes, I would very aggressively embark on lifestyle intervention, I would seek any help available to achieve that and I would also be in regular contact with my physician at least once every two or three years to make sure that I am not progressing toward diabetes.