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

AIM: To evaluate the sustainability of the benefits of continuous subcutaneous insulin infusion therapy in routine practice in a cohort of adults with diabetes.
METHODS: The clinical records of all adults starting continuous subcutaneous insulin infusion over 12 years 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.
RESULTS: Adequate data were available from 327 patients, of whom 71% were female. The patients' mean ± sd age was 41 ± 14 years, the mean ± sd (range) follow-up for continuous subcutaneous insulin infusion was 4.3 ± 2.7 (1-12) years. The mean ± sd HbA(1c) concentration fell by 8 ± 5 mmol/mol (0.7 ± 0.5%) at year 1 [to 63 ± 12 mmol/mol from 70 ± 18 mmol/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 ± 11 mmol/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 1.1 years), 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.
CONCLUSIONS: The 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.