Assessment of the effectiveness of long-term insulin pump therapy using a combined goal of HbA_1c decrease and absence...

Less than one third of patients with type 1 diabetes mellitus (T1DM) achieve the cut-off value proposed as good metabolic control by most guidelines, HbA_1c<7%. However, HbA_1c reductions and prevention of severe hypoglycemia (SH) have shown clinically relevant benefits. The study objective therefore was to assess the effectiveness of continuous subcutaneous insulin infusion (CSII) therapy at 5 years of follow-up in a cohort of patients attending a specialized unit using HbA_1c reduction and abscence of SH as combined goals.

A retrospective, observational study on 178 patients with T1DM who started CSII treatment at Hospital Clinic of Barcelona between 2003 and 2008. HbA_1c levels at baseline and after 5 years of treatment with CSII and presence or absence of SH were recorded. The combined variables calculated included: a) HbA_1c reduction by≥0.5 points and absence of SH in the last 2 years; b) HbA_1c at 5 years<7.5% and no SH in the last 2 years; c) HbA_1c<8.5% and no HG in the last 2 years, and d) HbA_1c reduction by≥0.5 points and/or HbA_1c<7.5% at 5 years with no SH in the last 2 years of follow-up.

Twenty-seven of the 178 patients were excluded due to loss to follow-up or CSII discontinuation. A total of 151 patients (aged 37.4±10.5 years, 64% women, diabetes duration of 19.2±10.7 years) were therefore analyzed. The 2 main reasons for starting CSII were suboptimal metabolic control (60.9%) and severe hypoglycemia/hypoglycemia unawareness (28.5%). HbA_1c levels in the total cohort and in patients with suboptimal metabolic control were 8.0±1.2 and 8.4±1.1% at CSII start and 7.8±1.2 and 8.0±1.3% at 5 years of treatment (P=.104 and P=.016) respectively. In the overall cohort, 55.5% of patients achieved at 5 years the combined goal of HbA_1c<7.5% and/or HbA_1c reductions≥0.5% without SH.

After 5 years of CSII therapy, more than half of the patients achieved the combined goal of significant HbA_1c reduction and absence of SH. The use of combined goals offers the opportunity to assess the effectiveness of T1DM treatment from a clinically more meaningful point of view.