Effectiveness of continuous subcutaneous insulin infusion in hypoglycaemia-prone type 1 diabetes

Abstract

The aim of this study was to quantify the impact of treatment of hypoglycaemia-prone type 1 diabetic subjects by continuous subcutaneous insulin infusion (CSII). A prospective analysis was carried out in patients attending a specialist insulin pump clinic. Type 1 diabetic patients (n=27) who had continued to suffer from frequent, unpredictable and disabling biochemical hypoglycaemia during multiple insulin injection therapy (MDI) were treated by CSII for up to a median of 17 months. Glycaemic control was unaltered by a median five months' renewed MDI: mean ± SD HbA1c 8.7±1.5 vs 8.8±1.3%. Subjects switched from isophane to glargine as long-acting insulin also failed to improve: HbA1c 9.0±1.4 vs 9.1±1.5%. After a median six months' insulin pump therapy, glycaemic control had improved, with a median (interquartile range) fall in HbA1c of 1.4(0.4-2.7)%. There was no systematic change in weight after instituting pump treatment. Glycaemic oscillations, day-to-day variability and hypoglycaemia frequency (percent self-monitored blood glucose values <3.5mmol/L) were also significantly reduced by CSII compared to MDI. We conclude that CSII is effective at improving overall control, glycaemic variability and hypoglycaemia frequency in subjects previously uncontrolled on MDI because of unpredictable hypoglycaemia. The magnitude of the change in HbA1c in hypoglycaemia-prone subjects is larger than expected in unselected type 1 patients and likely to have significant impact on microvascular disease risk. We recommend that National Institute for Clinical Excellence guidelines for CSII should explicitly include those with frequent, unpredictable biochemical hypoglycaemia. Copyright © 2005 John Wiley & Sons, Ltd.