Lower fasting blood glucose, glucose variability and nocturnal hypoglycaemia with glargine vs NPH basal insulin in subjects with Type 1 diabetes

Background and aims: To compare switching from NPH insulin (NPH) to insulin glargine (glargine) with continuing NPH for changes in fasting blood glucose (FBG) in patients with Type 1 diabetes on basal-bolus therapy with insulin lispro as bolus insulin. Secondary objectives included self-monitoring blood glucose, mean daily blood glucose (MDBG) and mean amplitude glucose excursion (MAGE) values alongside changes in HbA1c and safety profiles. Methods and results: This was a 30-week, parallel, open-label, multicentre study. Seven-point profiles were used to calculate MDBG and MAGE. Hypoglycaemia and adverse events were recorded by participants. FBG improved significantly with both glargine (baseline-endpoint change: -28.0 mg/dL; 95% CI: -37.3, -18.7 mg/dL; p < 0.001) and NPH (-9.8 mg/dL; 95% CI: -19.1, -0.5 mg/dL; p = 0.0374). The improvement was significantly greater with glargine than NPH (mean difference: -18.2 mg/dL; 95% CI: -31.3, -5.2 mg/dL; p = 0.0064). MDBG (-10.1 mg/dL; 95% CI: -18.1, -2.1 mg/dL; p = 0.0126) and MAGE (-20.0 mg/dL; 95% CI: -34.5, -5.9 mg/dL; p = 0.0056) decreased significantly with glargine, but not NPH although endpoint values were no different with the two insulins. Baseline to endpoint change in HbA1c was similar (-0.56 vs -0.56%) with no differences at endpoint. Overall hypoglycaemia was no different, but glargine reduced nocturnal hypoglycaemia ("serious episodes" with BG < 42 mg/dl, p = 0.006) whereas NPH did not (p = 0.123), although endpoint values were no different. Conclusion: Switching from NPH to glargine is well tolerated and results into lower FBG, and lower glucose variability while reducing nocturnal hypoglycaemia. These data provide a rationale for more aggressive titration to target with glargine in Type 1 diabetes.