Variations in the quality and sustainability of long‐term glycaemic control with continuous subcutaneous insulin infusion

Aims To investigate the pattern of changes in HbA 1c in people with Type 1 diabetes managed by long‐term Continuous subcutaneous insulin infusion. Methods We studied HbA 1c changes using computerized clinic records in 35 adult people with Type 1 diabetes and an elevated HbA 1c (≥ 64 mmol/mol, 8.0%) on multiple daily insulin injections, who were then switched to continuous subcutaneous insulin infusion for at least 5 years. Results We identified three subgroups with similar baseline HbA 1c but different long‐term responses to pump therapy: group A—those with improvement followed by deterioration (57%); group B—those with improvement that was sustained throughout the 5 years (31%); and group C—those where HbA 1c did not change significantly from baseline (12%). The patients in group C had a higher BMI : 31.0 ± 5.2 vs. 25.9 ± 3.3 vs. 25.2 ± 3.1 kg/m 2 (group C vs. group A and group B; P  = 0.02). Conclusions Improved glycaemic control with continuous subcutaneous insulin infusion was maintained over 5 years by 88% of people with Type 1 diabetes in this study, but there were variations in the long‐term efficacy, with some people improving and worsening, others maintaining strict control and a few subcutaneous insulin infusion ‘non‐responders’.