The Effect of Early Insulin Therapy on Pancreatic β-Cell Function and Long-Term Glycemic Control in Newly Diagnosed Type 2 Diabetic Patients

BACKGROUND/AIMS Based on the results of well designed clinical studies, intensive insulin therapy has been established to improve glycemic control in newly diagnosed diabetes. However, discrepancies exist between the findings of clinical trials and experiences in general practice. Furthermore, the efficacy of an early insulin therapy (EIT) - commonly used in general practice - on long-term glycemic control has not been established. Therefore, we evaluated the effects of EIT on pancreatic β-cell function and glycemic control using insulin-based methods widely employed in general practice. METHODS We performed a retrospective cohort study that initially involved reviewing patients' medical records. Following a thorough review, 61 patients who received either biphasic or prandial EIT at the time of diagnosis were enrolled. We then evaluated changes in β-cell function and glycemic control during a 48-month follow-up period. RESULTS Mean HbA1c decreased significantly as a result of EIT from 10.7 ± 1.8% to 6.2 ± 1.1% (p < 0.001). On average, 2.6 months was required to achieve an HbA1c value < 7%. EIT significantly improved the insulinogenic index. Glycemic control was well maintained for 48 months. More than 70% of patients were able to maintain glycemic control following lifestyle modifications or treatment with oral antidiabetic drugs. No significant differences were identified between patients receiving biphasic EIT and prandial EIT in terms of glycemic control or pancreatic β-cell function. CONCLUSIONS Our results suggest that regardless of the method of delivery, EIT significantly improves β-cell function and facilitates long-term glycemic control in patients with newly diagnosed type 2 diabetes mellitus.