Sustained benefit of continuous subcutaneous insulin infusion on glycaemic control and hypoglycaemia in adults with Type 1 diabetes

AimTo evaluate the sustainability of the benefits of continuous subcutaneous insulin infusion therapy in routine practice in a cohort of adults with diabetes. MethodsThe clinical records of all adults starting continuous subcutaneous insulin infusion over 12years at our centre were included in this study. Baseline and mean annual HbA(1c) levels were recorded. The frequency of mild-to-moderate and severe hypoglycaemia and hypoglycaemia awareness were analysed in a subgroup. ResultsAdequate data were available from 327 patients, of whom 71% were female. The patients' meansd age was 4114years, the meansd (range) follow-up for continuous subcutaneous insulin infusion was 4.32.7 (1-12) years. The meansd HbA(1c) concentration fell by 85mmol/mol (0.7 +/- 0.5%) at year 1 [to 63 +/- 12mmol/mol from 70 +/- 18mmol/mol (7.9 +/- 1.1% from 8.6 +/- 1.6%); P<0.0005], sustained to year 5. In patients with initial poor control, HbA(1c) dropped by 12 +/- 11mmol/mol (1.1 +/- 1.0%; P<0.0005) at year 1, sustained to year 6. The percentage of patients with 5 mild to moderate hypoglycaemic episodes per week fell from 29 to 12% (n=163; P=0.006). In the subgroup (n=87; follow-up 2.5 +/- mean +/- sd 1.1years), the frequency of severe hypoglycaemia fell from 0.6 +/- 1.7 episodes per patient per year to 0.3 +/- 0.9 (P=0.047). Of 24 patients with impaired awareness of hypoglycaemia (Gold score 4), the mean +/- sd Gold score improved from 4.9 +/- 0.9 to 3.8 +/- 1.7 (P=0.011). Nine people regained awareness. No deterioration in HbA(1c) was seen in the hypoglycaemia-prone groups. ConclusionsThe benefits of continuous subcutaneous insulin infusion with regard to improving glycaemic control and reducing hypoglycaemia frequency, along with improvement in hypoglycaemia awareness without deterioration in glycaemic control, can be sustained over several years in clinical practice.