QUEBEC CITY — Diabetes care is “on the path to automated glucose control,” with the promise of “intelligent” insulin pumps and devices in the near future, according to John Walsh, P.A.
Today's insulin pumps have an impressive capacity to improve currently suboptimal glycemic control in many patients with type 1 diabetes, he said at the annual meeting of the Canadian Diabetes Association and the Canadian Society of Endocrinology and Metabolism.
“Our current approach to diabetes does not work,” said Mr. Walsh, a certified diabetes educator and author of “Pumping Insulin” and other books on diabetes. “For most patients, the hemoglobin [Hb] A1c goal of 6.5% or less is not being met.”
Patients with diabetes must make complex decisions about carbohydrate intake and insulin dosing several times every day. They often make poor decisions that may lead to imbalances in their blood glucose levels.
Insulin pumps can at least partially remedy this, but studies of patients who use pumps show only minimal improvements in their HbA1c levels Mr. Walsh said.
“I don't think we've seen anywhere near the capacity that can be achieved with pumps,” he said. It is partly a matter of clinicians lacking experience with pumps and needing to become more familiar with the formulas for programming them. But it is also a matter of not using the data that is collected by pumps and glucose meters to look for patterns and correct problems, he said.
Establishing the correct total daily dose (TDD) of insulin is probably the most important part of programming a pump; all other dosing formulas are based on the TDD. An appropriate starting TDD can be calculated using the patient's weight in kilograms, divided by 1.8, to yield the number of insulin units, he said.
The basal dose can be calculated at 50% to 60% of the TDD, and carbohydrate boluses can be calculated using what he calls “the 500 rule”: Dividing 500 by the TDD gives the number of grams of carbohydrate that can be covered by 1 unit of bolus insulin. For example, if a patient's TDD is usually 50 units of insulin, applying “the 500 rule” would show that 10 g of carbohydrate requires 1 extra bolus unit of insulin, he said.
Once this basic pump formula is established for a patient, it can be fine-tuned. Advanced pumpers can calculate exact correction boluses needed to lower high glucose readings, and with modern pumps they can also make adjustments to account for any unused insulin that is still in their system (known as “bolus on board”).
As physicians become more familiar with pump formulas and programming, they should be able to access the pump's stored data to track a patient's dosing and blood glucose patterns and identify possible solutions to problems, Mr. Walsh said.
“Today's devices collect most of the necessary information about a patient's dosing schedule and carbohydrate intake, but it takes experience for a clinician to be able to quickly access that information and use it to make a treatment decision,” he said.
The workload involved in this kind of care is heavy and will remain that way until pumps become more intelligent and begin taking over more of the analysis involved, he said.
“Until there is a device that can give patients immediate advice and foresee potential problems, HbA1c will not reach target levels for most patients, and health care involvement will remain heavy,” Mr. Walsh predicted.