Bolus calculator in personal insulin pumps — advantages, differences and practical tips

Abstract

The widespread use of personal insulin pumps in the treatment of type 1 diabetes has significantly improved the effects of therapy. Better metabolic control of diabetes, but also increased comfort of life and professional opportunities have been achieved. One of the functions that increased the effectiveness of insulin therapy using a personal insulin pump is the bolus calculator. The bolus calculator function allows the user to dose their insulin more accurately before meals and to correct hyperglycaemia. The bolus calculator algorithms in insulin pumps of individual manufacturers differ in the way they calculate the correction dose and the amount of so-called active insulin. Consequently, with the same treatment parameters, individual bolus calculators may offer a different dose of insulin. Understanding the principles of the bolus calculator by therapeutic team members and patients is very important for proper diabetes education and diabetes

Addendum 1: Forum for Injection Technique and Therapy Expert Recommendations, India

“…Proper blood glucose selfmonitoring using a blood glucose meter or CGM is essential [98]. The use of an automated bolus calculator is now widely accepted by patients and has been shown to improve glucose control [89] and reduce glycaemic variability [99].…”

“…Typically, when setting the bolus calculator, the following parameters must be determined individually for each patient [99]:…”

“…1. Insulin-to-carbohydrate ratio (ICR): For the initial determination of ICR, the rule of 500 should be used; 500 is divided by the total daily insulin dose (DDI) to get the grams covered by 1 unit of insulin [99]; 500/50 = 10 g. The normal recommendation is to give 1 unit of insulin for every 15 g. However, this formula is just the starting point and ICR needs to be tweaked further for each individual. 2.…”

“…2. Insulin sensitivity (correction factor): 1800 rule is used in which 1800 is divided by the DDI to get the average blood glucose reduction after administration of 1 unit of insulin [99]. Like ICR, this formula only provides a standard starting reference and needs to be personalized.…”

“…It is vital to include this calculation in bolus dose calculators to avoid overdosing and stacking. In adults, this parameter is programmed for 3-4 h. It depends on the bolus size, and for boluses [ 10-15 units, the programmed time can be prolonged to 5 h[99].…”