Fasting plasma glucose 6–12 weeks after starting insulin glargine predicts likelihood of treatment success: a pooled analysis

AIMS To evaluate whether fasting plasma glucose values measured early during insulin therapy can identify patients with Type 2 diabetes who may not achieve adequate glycaemic control after 6 months and will require additional treatment. METHODS Patient-level data from seven prospective, randomized, controlled studies using treat-to-target methods were pooled to evaluate the efficacy of insulin glargine. Fasting plasma glucose was measured at baseline, week 6 or 8 (6/8) and week 12. HbA(1c) was measured at week 24 to assess glycaemic control. RESULTS One thousand and thirty-six patients (56% male, 81% white) were included in the analysis (mean age 56.3 years; duration of diabetes 8.4 years). Baseline mean fasting plasma glucose was 11.2 mmol/l and mean HbA(1c) was 73 mmol/mol (8.8%). After 24 weeks of treatment, mean HbA(1c) decreased to 53 mmol/mol (7.0%); 56% of patients reached a target HbA(1c) ≤ 53 mmol/mol (7.0%). Significant correlations with week 24 HbA(1c) were obtained for fasting plasma glucose measured at week 6/8 and week 12 (r = 0.32; P < 0.0001 for both). Patients with fasting plasma glucose > 10 mmol/l at week 6/8 or week 12 were significantly less likely to achieve the HbA(1c) target at the end of treatment than patients with fasting plasma glucose < 8.9 mmol/l (P < 0.0001 for both). If fasting plasma glucose was > 10 mmol/l at week 6/8 or week 12, patients had only a 27% chance of reaching the HbA(1c) goal. CONCLUSIONS Fasting plasma glucose remaining > 10 mmol/l after 6-12 weeks of glargine therapy indicates that reaching target HbA(1c) ≤ 53 mmol/mol (7.0%) is unlikely and calls for individualized attention to consider further therapeutic options.