Liraglutide as Add-On Therapy to Insulin in Type 2 Diabetes Mellitus: A Retrospective, Observational Study From a Daily Clinical Practice Setting in Switzerland

Introduction: In most patients with type 2 diabetes mellitus (T2DM) and progressive beta-cell insufficiency, insulin therapy is required to achieve sufficient glycemic control. However, insulin therapy may lead to weight gain and increasing risk of hypoglycemia. Glucagon-like peptide-1 receptor agonists are being used as add-on therapy to insulin with favorable metabolic effects. Nonetheless, to date only few studies exist reporting on the combination of liraglutide and insulin with a short follow-up period. The aim of this study was to evaluate the efficacy and safety of liraglutide as add-on to insulin in patients with T2DM over a time period of up to 24-28 months. Methods: Data of patients with T2DM, treated with insulin and liraglutide at an outpatient clinic in a tertiary referral hospital from October 2009 until December 2011 were retrospectively examined (n = 36). Glycated hemoglobin (HbA1c), weight, total daily insulin dose and side effects were assessed 5-8 months prior to liraglutide, at baseline and at follow-up visits after 3, 6, 12-16 and 24-28 months. Results: Median HbA1c decreased significantly from 7.7% [interquartile range (IQR) 7.0-8.6] at baseline to 6.8% (IQR 6.5-7.7, p = 0.001) at 3 months and 6.9% (IQR 6.3-7.6, p = 0.0001) at 6 months, but re-increased thereafter (at 24-28 months, median 7.5%, IQR 7.1-8.2, p = 1.0). Median weight decreased significantly from 99.8 kg (IQR 81-110) at baseline to 97.7 kg (IQR 81.2-108.2, p = 0.027) at 3 months, but rose again thereafter. Insulin dosage did not change significantly over time. No severe hypoglycemia or major side effects occurred. Conclusions: In this observational study, adding liraglutide to insulin in daily clinical practice reduced HbA1c significantly within 6 months, but there may be a non-sustainable effect during long-term treatment.