Improvement of both fasting and postprandial glycemic control by the two-step addition of miglitol and mitiglinide to basal insulin therapy: a pilot study

Background: Combination therapy consisting of basal insulin and oral hypoglycemic agents (OHAs) is effective for the treatment of type 2 diabetes (T2DM) that cannot be adequately controlled using OHAs alone. Though basal insulin with metformin or sulfonylurea is an effective therapy, it cannot reduce postprandial glycemia without the risk of hypoglycemia. We examined a two-step regimen consisting of the addition of postprandial hypoglycemic agents (an alpha-glucosidase inhibitor and a glinide) in patients whose T2DM was poorly controlled using basal insulin therapy. Methods: Inpatients between the ages of 30-79 years who had T2DM and an HbA1c level of more than 7.0% were recruited. The patients were treated with once-daily insulin glargine with or without metformin, depending on the patient's age and renal function. Insulin glargine was titrated to achieve a target fasting glucose level of 70-130 mg/dL as a first step (STEP0). If the 2-hour postprandial glucose (PBG) level was higher than the target of 180 mg/dL, miglitol treatment (150 mg/day) was initiated, with dose adjustments (75-225 mg) allowed depending on abdominal symptoms and the PBG (STEP1). If the PBG of the patients remained higher than the target after 3 days of treatment, mitiglinide (30 mg/day, titrated up to 60 mg) was added (STEP2). We then evaluated the proportion of patients who achieved the target PBG before and after the two-step regimen. Continuous Glucose Monitoring (CGM) was performed throughout the two-step protocol in most of the patients. Results: Of the 16 patients who were recruited (median age, 67.0 [58.0-71.0] years; body mass index, 25.0 [22.0-27.9] kg/m(2); HbA1c level at admission, 9.1% [8.35-10.4%]), 1 patient (6.25%) achieved the target PBG at STEP 0 and 14 patients (87.5%) had achieved the target PBG at the end of the treatment protocol (P = 0.002). CGM showed a significant decrease in the glucose level at each step of the protocol. The standard deviations in the CGM glucose levels for 24 hours, MAGE, and M-value also improved. Conclusions: The two-step addition of postprandial hypoglycemic agents to basal insulin therapy is potentially effective and safe for decreasing both the fasting and postprandial glucose levels.