Kevin A. Peterson, MD, MPH
University of Minnesota Medical School
Minneapolis, MN
This man is already showing early signs of microvascular disease. At 52 he will need better control to prevent progressive damage to his eyes over the next 30+ years he can expect to live. He is already on glargine and metformin. Great! Certainly insulin provides the surest guarantee for lowering his A1c to safer levels.
Information gathering
I would start by taking him off the sulfonylurea (SU). With wide variability in action over the course of the day, the SU will present the greatest risk of hypoglycemia as work to get his blood sugar down to a safer range proceeds.
Then we need some more information. We know this patient is failing to achieve good control, but we don’t really know the cause of the problem. I expect that he has already pushed the glargine up as high as he can tolerate. This will be limited either by intermittent hypoglycemia in the late afternoon as the glimiperide kicks in on days that he has not been able to have a regularly scheduled lunch, or by morning hypoglycemia from the glargine. Stopping the SU should help prevent any late afternoon hypoglycemia, and might enable us to increase the glargine with a subsequent drop in the A1c—one less drug, and better control. On the other hand, if the glargine is already maximized, then we need to find out when the hyperglycemia is occurring. That will be helped by an evaluation of his dietary habits, and by asking for some pre- and postprandial blood sugars.
It sounds like he is doing pretty well until getting home. Checking before eating in the evening and adding a four-hour postprandial measure before bed will be educational by identifying better food options, and by seeing if higher sugars are present at that time. If his blood sugar is going up over supper, then it is time to begin to consider adding some prandial insulin. Of course, better food choice is essential. No amount of short-acting insulin will allow him to continue to eat badly, and weight control will need to be addressed with behavioral and perhaps family interventions. But preprandial and postprandial blood sugars will show both of us the effect of his meal choices, and will prepare for introduction of short-acting insulin.
A stepwise approach to short-acting insulin
When I initiate short-acting insulin in a person like this with type 2 diabetes, I generally start with one meal at a time, rather than introducing the challenge of prandial insulin at each meal. I start with the biggest meal of the day and then recheck. It may be that one shot at supper will result in much better control, and will be better accepted and easier to manage than three shots per day. If control isn’t achieved, then I look for the next largest meal. Many people don’t eat three meals a day, so I start off by tailoring insulin to real eating habits.
Although adding short-term insulin may triple rates of hypoglycemia, there is no more certain way of lowering A1c. And this patient’s overall safety and the preservation of his vision demand a lower A1c. Education is essential, and will go a long way in preventing problems. As he begins to get better control, he will need to learn more about eating, exercise, sick days, precautions while driving, and how to use insulin. He should get started with learning more right away.
Then there is the weight control. This is a great time to bring the family in to help. The kids need to know what Dad is going through, and to see what they can do to change the environment. Behavioral change is a family affair.
It is often said that the basal/prandial split should be 50/50, but this patient’s being on metformin and glargine will alter this. I would avoid adding correctional doses, and would not vary the dose by carbohydrate load, at least not until he had more education. Instead, I’d start with a specific dose, and adjust if the patient continued to have significantly higher readings four hours later. Much more can be done, but this is simple and safe. If he skips the meal, skip the insulin.
Conclusion
There is no doubt that we can lower this patient’s A1c below 7 using a basal bolus approach and adding prandial insulin. Although I can’t be sure if lowering his A1c from 8.0 to less than 7.0 will prevent cardiovascular disease, it will certainly will help prevent microvascular disease, and is the best way to help him keep his eyesight.