Patterns of glycaemic control in patients with type 2 diabetes mellitus initiating second-line therapy after metformin monotherapy: Retrospective data for 10 256 individuals from the United Kingdom and Germany.

AIM: To investigate determinants of change in glycated haemoglobin (HbA1c) in patients with type 2 diabetes mellitus (T2DM) at 6 months after initiating uninterrupted second-line glucose-lowering therapies. MATERIALS AND METHODS: This cohort study utilized retrospective data from 10 256 patients with T2DM who initiated second-line glucose-lowering therapy (switch from or add-on to metformin) between 2011 and 2014 in Germany and the UK. Effects of pre-specified patient characteristics on 6-month HbA1c changes were assessed using analysis of covariance. RESULTS: Patients had a mean (standard error [SE]) baseline HbA1c of 8.68% (0.02); 28.5% of patients discontinued metformin and switched to an alternative therapy and the remainder initiated add-on therapy. Mean (SE) unadjusted 6-month HbA1c change was -1.27% (0.02). When adjusted for baseline HbA1c, 6-month changes depended markedly on the magnitude of the baseline HbA1c (HbA1c <9%, -0.45% per unit increase in HbA1c; HbA1c ≥9%, -0.87% per unit increase in HbA1c). Adjusted mean 6-month HbA1c reductions showed slight treatment differences (range, 0.92-1.09%; P < .001). Greater reductions in HbA1c were associated with second-line treatment initiation within 6 months of T2DM diagnosis (1.36% vs 1.03% [P < .001]) and advanced age (≥70 years, 1.13%; <70 years, 1.02% [P < .001]). CONCLUSIONS: Many patients with T2DM have very high HbA1c levels when initiating second-line therapy, indicating the need for earlier treatment intensification. Patient-specific factors merit consideration when making treatment decisions.