Long-term outcome of insulin pump therapy: reduction of hypoglycaemia and impact on glycaemic control.

Abstract

To determine the long-term outcome of continuous subcutaneous insulin infusion (CSII) in Type 1 diabetes according to Catalan National Health Service indications. Retrospective observational study including 178 patients with Type 1 diabetes who started CSII treatment in our centre (2003-2008). All patients were followed in our CSII programme for outpatients for at least 5 years. Data on annual HbA1c levels were collected, and the main indication for starting CSII was analysed. Twenty-seven of 178 patients were excluded because of loss to follow-up or withdrawal from CSII, thus 151 patients (aged 37.4 ± 10.5 years, 64% women) were analysed. The main indications for starting CSII were suboptimal metabolic control (60.9%), severe hypoglycaemia/hypoglycaemia unawareness (25.5%) and others (13.6%). HbA1c was 64 ± 13 mmol/mol (8.0 ± 1.2%) at the start of CSII and 62 ± 13 mmol/mol (7.8 ± 1.2%) after 5 years in the total cohort (P = 0.1). The severe hypoglycaemia rates were 0.66 ± 1.61 and 0.17 ± 0.42 episodes/patient/year (P < 0.001). In patients with suboptimal metabolic control, HbA1c decreased from 68 ± 12 mmol/mol (8.4 ± 1.1%) to 64 ± 14 mmol/mol (8.0 ± 1.3%) (P = 0.016), with 37.4% of those in this group having an HbA1c ≤ 58 mmol/mol (7.5%) after 5 years. In patients starting CSII due to severe hypoglycaemia the problem was considered resolved in 93%, and in 64% of those starting CSII because of suboptimal glycaemic control, HbA1c improved significantly. CSII therapy achieves and maintains its efficacy mainly in terms of reducing severe hypoglycaemia. In the whole group of patients, the reduction in HbA1c is transient and disappears after 5 years.