Effect of switching from NPH insulin to insulin glargine on glycemic control in Japanese type 1 diabetic patients

To evaluate the effect of switching from NPH insulin to insulin glargine on glycemic control in Japanese type 1 diabetics we monitored the HbAic values and insulin dosage in 46 type 1 diabetic patients for 6 months after switch. The consecutive mean HbA1c values decreased until 6 months after switching (8.6±1.1 %→7.5±0.9%, p<0.0001). Although the total insulin dosage required significantly increased after switching, there was no increase in body weight. The frequency of hypoglycemia significantly decreased after switching. Comparison of baseline profiles between the patients with more than a 1% improvement in HbA1c and the other patients revealed that only HbA1c values were significantly higher in the improved group (9.3±1.3% vs. 8.1±0.7%, p<0.001). An analysis of all subjects showed that the HbA1c values at baseline were positively correlated with improvement of HbA1c values (r=0.679, p<0.0001). Based on these results, we conclude that switching Japanese type 1 diabetes patients, from NPH insulin to insulin glargine is useful in clinical practice, especially in poorly controlled patients.