OBJECTIVE To assess whether clinical characteristics and simple biomarkers of β-cell failure are associated with individual variation in glycemic response to GLP-1 receptor agonist (GLP-1RA) therapy in patients with type 2 diabetes.
RESEARCH DESIGN AND METHODS We prospectively studied 620 participants with type 2 diabetes and HbA1c ≥58 mmol/mol (7.5%) commencing GLP-1RA therapy as part of their usual diabetes care and assessed response to therapy over 6 months. We assessed the association between baseline clinical measurements associated with β-cell failure and glycemic response (primary outcome HbA1c change 0–6 months) with change in weight (0–6 months) as a secondary outcome using linear regression and ANOVA with adjustment for baseline HbA1c and cotreatment change.
RESULTS Reduced glycemic response to GLP-1RAs was associated with longer duration diabetes, insulin cotreatment, lower fasting C-peptide, lower postmeal urine C-peptide–to–creatinine ratio, and positive GAD or IA2 islet autoantibodies (P ≤ 0.01 for all). Participants with positive autoantibodies or severe insulin deficiency (fasting C-peptide ≤0.25 nmol/L) had markedly reduced glycemic response to GLP-1RA therapy (autoantibodies, mean HbA1c change −5.2 vs. −15.2 mmol/mol (−0.5 vs. −1.4%), P = 0.005; C-peptide <0.25 nmol/L, mean change −2.1 vs. −15.3 mmol/mol (−0.2 vs. −1.4%), P = 0.002). These markers were predominantly present in insulin-treated participants and were not associated with weight change.
CONCLUSIONS Clinical markers of low β-cell function are associated with reduced glycemic response to GLP-1RA therapy. C-peptide and islet autoantibodies represent potential biomarkers for the stratification of GLP-1RA therapy in insulin-treated diabetes.
- Received February 4, 2015.
- Accepted July 4, 2015.
- © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.