How is the starting basal rate calculated when commencing insulin pump therapy, and what is the recommended initial reduction?

When commencing insulin pump therapy, the total daily background insulin dose from the previous regimen is reduced by 20–25%. The remaining dose is divided by 24 to give the hourly starting basal rate, programmed initially as one flat rate.

The evidence specifies a basal reduction of 20–25% when starting continuous subcutaneous insulin infusion. For example, if a person is taking 12 units of long-acting insulin twice daily, the total daily background insulin is 24 units. A 20% reduction is 4.8 units, leaving 19.2 units per day. Dividing this by 24 gives an initial flat basal rate of 0.8 units per hour. The basal rate is then adjusted later based on the individual's requirements, alongside their insulin-to-carbohydrate ratios and correction factors as established on their multiple injection regimen.