Baseline and 1-year interim follow-up assessment of Japanese patients initiating insulin therapy who were enrolled in the cardiovascular risk evaluation in people with type 2 diabetes on insulin therapy study: an international, multicenter, observational study

BACKGROUND: The Cardiovascular Risk Evaluation in people with type 2 Diabetes on Insulin Therapy (CREDIT) study is an international, multicenter, observational study designed to assess metabolic parameters and cardiovascular risk of patients with type 2 diabetes mellitus (T2DM) on insulin therapy. The present report summarizes results at baseline and 1-year follow-up for the cohort of Japanese patients. METHODS: Male and female patients (n = 511), aged >40 years, with T2DM for >1 year, treated with insulin therapy for ≥1 month and <6 months were eligible for participation in the study. Glycemic and lipid parameters, duration of diabetes, diabetic complications, oral antidiabetic medications, and all hypoglycemic episodes were recorded. Effectiveness was assessed based on changes in clinical parameters and attainment of target HbA1c levels. Safety was evaluated based on episodes of hypoglycemia and weight gain. RESULTS: At baseline, the mean ± SD duration of diabetes was 11.8 ± 8.8 years. Microvascular and macrovascular diabetic complications were present in 83.4% and 25.1% of patients, respectively. At the 1-year follow-up, significant improvements were observed in mean HbA1c (10.3 ± 2.0% vs. 7.5 ± 1.3%, P < .001), fasting plasma glucose (217.3 ± 80.8 mg/dL vs. 139.0 ± 48.7 mg/dL, P < .001), and postprandial plasma glucose levels (296.1 ± 96.0 mg/dL vs. 178.2 ± 68.6 mg/dL, P < .001) compared with baseline. Mean total cholesterol (P < .001), low-density lipoprotein cholesterol (P < .001), triglycerides (P < .01), and diastolic blood pressure (P < .01) also significantly decreased. Good glycemic control (HbA1c < 7.0%) was achieved in 40% of patients at the 1-year follow-up. Glycemic control tended to be better in patients with lower baseline HbA1c levels (P < .01). Patients with a shorter duration of diabetes were more likely to achieve glycemic control and discontinue insulin for diabetes control at the 1-year follow-up (P < .05 for trend). Symptomatic hypoglycemic episodes occurred in 21.8% of patients over 6 to 12 months. CONCLUSIONS: Our results suggest that insulin treatment is an effective and safe therapeutic option in Japanese patients with T2DM, and earlier insulin initiation might be associated with better glycemic control.