Automated insulin delivery for type 1 diabetes

Purpose of review Automated insulin delivery using the subcutaneous site for both glucose sensing and insulin delivery, while not commercially available, is starting to be implemented in the research environment. Here, we review issues with glucose sensing and insulin delivery algorithms that need to be resolved in order to achieve a closed-loop system. Recent findings Glucose sensing technology is improving. New studies demonstrating minimal delay in the subcutaneous interstitial fluid glucose response are reviewed, together with early studies indicating longer delay. The pharmacokinetics/pharmacodynamics of subcutaneous insulin, which pose a significant obstacle to closing the delivery loop, are also reviewed, together with approaches being used to develop algorithms to overcome the delay in insulin absorption from this site. Closed-loop data using the Medtronic MiniMed external Physiologic Insulin Delivery system are presented. Summary Initial closed-loop data in both animals and humans suggest that a completely automated insulin delivery system is attainable, although substantial research remains to be conducted prior to such a system being available for home patient use.