What are the advantages and disadvantages of continuous subcutaneous insulin infusion (CSII) compared to insulin injections?

Compared with insulin injections, CSII offers more consistent and better-absorbed insulin delivery, fewer needle injections, flexible basal delivery around activity or illness, more precise small dose adjustments, and improved patient experience and satisfaction. Its disadvantages are that the user must be attached to the pump almost continuously, there is an infection risk if the cannula is not changed every 2–3 days, a higher risk of DKA if delivery is interrupted, day-to-day practicalities can be challenging especially for new users, and it costs the NHS more than pen/injection delivery.

The evidence lists the main advantages of CSII over insulin pens/injections: insulin is absorbed better and delivered more consistently; fewer needle injections are needed, which helps people with needle phobia; basal insulin delivery is flexible and can be adjusted for unplanned activity or illness more easily and immediately; small incremental changes to insulin delivery allow greater dose precision; and patient experience and satisfaction are improved. The disadvantages include the need to be attached to the device 24 hours a day, removing it only briefly for showering, swimming, or contact sports; the risk of infection if the cannula is not changed with the recommended frequency of every 2–3 days; an increased risk of diabetic ketoacidosis if pump delivery is interrupted, because insulin absence can occur very quickly; challenging day-to-day management practicalities, particularly when users are new to CSII; and higher cost to the NHS compared with insulin delivery via pen or injections.