Basal/Bolus Therapy: Combination of Insulin Pump and Lantus
During my outpatient clinic last week, I was queried about the "untethered regimen" in which the person with diabetes uses both Lantus and the insulin pump. I have heard Dr. Steven Edelman (an adult endocrinologist and person with type 1 diabetes) talk about this regimen in person and in a diabetes conference.
What is it? The "untethered regimen" is such that Lantus is given as an injection to provide approximately 75 percent of basal insulin with the remainder (25 percent) given by the pump. The pump continues to provide bolus insulin for correction and carbohydrates. Generally, most diabetes healthcare providers recommend either insulin pump therapy OR multiple daily injections with Lantus once (or occasionally twice daily) or Levemir (twice daily or occasionally once daily) along with rapid acting insulin for boluses to avoid confusion. Most feel that it is hard enough using one regimen rather than making one’s insulin regimen even more complicated by combining insulin pump and shots.
In considering this regimen, Dr. Edelman recommends taking approximately 75 percent of basal requirements as Lantus before bedtime, with the remaining 25 percent as basal rate. For example, if a person with type 1 diabetes is on 60 units/day and receives 40 percent of the total daily dose as basal rate (24 units), one would give 18 units of Lantus at bedtime (75 percent) and the remainder, 6 units (25 percent), as a basal rate over 24 hours (6/24= 0.25 units/hour). One would continue to use the pre-programmed insulin/carbohydrate ratios, insulin sensitivity factors (correction factors), insulin "onboard" feature, etc. One also may continue to use the special pump features such as "extended bolus, square/dual wave blousing, etc., to assist in the control of blood sugars especially with high carbohydrate/high fat meals.
There are, indeed, advantages to consider if one wishes to try the "untethered approach."
- The pump may be removed for extended periods of time (greater than 1 hour). Removing the pump is helpful if one is exercising for a prolonged period of time, athletic competitions, etc., as the Lantus serves as background basal insulin.
- If the pump is removed, there is less danger of becoming hyperglycemic or developing ketones. A word about ketones: if there is any pump malfunction, occlusion of the catheter, or any other problems resulting in the discontinuation of basal or bolus insulin, the pumper is in great danger of developing ketones rapidly due to the absolute lack of insulin. Thus, if one has received background Lantus, one always as basal insulin on board.
- If someone is going to the beach on summer break, one only needs to hook up the pump to give insulin for corrections or boluses. The amount of Lantus injected may vary depending on the amount of exercise planned. Dr. Edelman’s summer regimen consists of wearing the pump Monday through Friday with 75 percent of basal insulin as Lantus and 25 percent basal programmed more than 24 hours in the pump. On Friday night, he takes the full amount of required basal insulin (100%) as Lantus (or Levemir) and totally removes the pump on the weekend. For meal boluses and blood sugar corrections he uses the insulin pen. My diabetes program nursing coordinator does a similar routine all year round on the weekends. She wears her pump on the weekdays and then on the weekends, removes her pump and uses Levemir and rapid acting insulin.
In conclusion, the "untethered regimen" may be very effective for adolescents and young adults who participate in athletics and must disconnect their pumps for many hours, and can also provide backup basal insulin for anyone who needs to disconnect frequently. I would however, strongly caution you to work with your diabetes healthcare team to determine the best routine for you, as this may not be appropriate for many individuals. My goal is to educate everyone about what is "out" there and then for you to discuss the options that are best for you based on your lifestyle along with the advice and support of your diabetes team.
Fran Cogen, M.D., C.D.E., is the director of the Childhood and Adolescent Diabetes Program at Children’s National Health System. She wrote about diabetes for HealthCentral.