Insulin tolerance test predicts non response vs. sustained efficacy of Liraglutide on glycemic control in type 2 diabetes patients: A prospective real-world setting study

Aims: Less than half of type 2 diabetes patients treated with Glucagon-Like Peptide 1 (GLP-1) analogs displays good glycemic control, according to real life studies. Predictive markers of inefficacy/efficacy are therefore needed. The effectiveness of Liraglutide in terms of glycemic control and weight loss was then evaluated according to putative predictive parameters.

Methods: 80 type 2 diabetes patients treated with Liraglutide were included in this prospective study. An Insulin Tolerance test (ITT) was performed at baseline to calculate velocity of C-Peptide decrease (C-peptide T½). Several clinical and biological parameters including HbA_1c and weight were assessed at baseline and after 12, 24, 52 and 104 weeks of treatment.

Results: HbA_1c decrease over the follow-up period was highly associated with C-peptide T½. A mean fall of 0.7% of HbA1c (7.7 mmol/mol) was predicted with 82% sensitivity and 80% specificity by C-peptide T½. In patients with rapid response during ITT (C-peptide T½ < 120 min), a HbA1c decrease of 1.5% (16.5 mmol/mol) was constantly found (p = .002) all over the follow-up. HbA1c remained unmodified for the rest of the patients (p = .34) compared to baseline. HbA_1c evolution was not predicted by diabetes duration. Weight loss was predicted only by low baseline C-peptide plasma level.

Conclusions: This study suggests ITT as an efficient test to discriminate non-response from long-term efficacy before initiating Liraglutide. ITT could therefore help avoiding "try and see" prescription pattern by using a more precise and patient-centered strategy in order to reduce inertia in adapting treatment and so reduce subsequent complications.