Effects of lifestyle modifications on patients with type 2 diabetes: The Japan Diabetes Complications Study (JDCS) study design, baseline analysis and three year-interim report

Background: Lifestyle modifications may affect the development of diabetes and prevent complications. However, there is no direct evidence to show that lifestyle intervention is beneficial for patients with established type 2 diabetes. Objective: The ultimate goal is to determine whether long-term lifestyle intervention can improve glycemic control and prevent complications in patients with type 2 diabetes. This initial report on a multi-year study describes protocols and the analysis of baseline data and three-year interim results. Design: The study was a randomized, controlled, multi-centre, prospective intervention trial. The trial included patients from 59 Japanese institutes specializing in diabetes care. Patients: The study enrolled 2205 patients with previously diagnosed type 2 diabetes. Intervention: The lifestyle modification program included intensive lifestyle management at each outpatient clinic visit and frequent telephone counseling. The intervention group received educational materials concerning the importance of lifestyle and behavioural changes, a diary to record progress of laboratory and other data, and a pedometer. Measurements: Parameters and indices related to glycemic control, diabetic complications, dyslipidemia, hypertension, obesity, and atherosclerosis were measured several times a year. Results: Small but significant differences in HbA1c levels between the intervention (INT) and conventional (CON) therapy groups appeared as early as two years after the start of intervention and were maintained in the third year (CON group, 7.78 +/- 1.27 % vs. INT group, 7.62 +/- 1.20 %, the initial HbA1c level was 7.80 +/- 1.42 % for the CON group and 7.68 +/- 1.28 % for the INT group). Data on differences in occurrence of micro- or macrovascular complications are not yet available. Conclusions: The effect of lifestyle modification on improving the glycemic control of patients with established type 2 diabetes mellitus was small but significant three years after initiation of the intervention.