Flexible, Intensive vs. Conventional Insulin Therapy in Insulin-Naive Adults With Type 2 Diabetes - a Non-Blinded, Randomized Controlled Cross-Over Clinical Trial of Metabolic Control and Patient Preference

Hypothesis In the undertaken study we tested the hypothesis that flexible, intensive and conventional insulin therapy in insulin-naive adults with type 2 diabetes are equally effective in regards to metabolic outcomes. We hypothesized that younger participants in employment would prefer flexible, intensive insulin therapy.

Flexible, intensive and conventional insulin therapy CIT consisted of twice daily injections of premixed insulin (30% regular insulin, 70% NPH-insulin) before breakfast and dinner. Participants followed individually adjusted diet plans with fixed amounts of carbohydrates. Daily blood-glucose self-control was performed before insulin injections. Participants documented blood glucose readings and insulin dosage. Limited self-adjustment of insulin dosage was taught and encouraged in the DTTP, i.e. variance of up to 4 IU insulin per injection.

In FIT, participants measured blood glucose before main meals and at bedtime and adjusted regular insulin dosages to actual blood glucose levels and their desired carbohydrate intake on a meal by meal basis. When necessary, NPH insulin was added at bedtime. Additional administration of oral antidiabetic drugs was not permitted.

Study design, randomization and intervention The trial was designed as a clinical, prospective, randomized, non-blinded, single center, cross-over pilot study.

After randomization, participants started insulin therapy either with FIT or CIT and completed a Diabetes Treatment and Teaching Program on an out-patient basis. In this four week run-in period with weekly visits, individual insulin dosage and carbohydrate intake was determined (figure 1). The run-in was followed by an 8 week study sequence until cross-over. At cross-over, participants were given one structured teaching session for refreshing and switched from CIT to FIT (Group A) or FIT to CIT (Group B), respectively. After a one week run-in period for insulin dose-adjustment, participants completed the second 8 week study sequence. Regular visits were held at the beginning and at the end of both study sequences. Additional visits were held after 2 weeks, to adjust therapy if necessary. During visits, a study team consisting of a diabetologist and a specially trained nurse educator analyzed personal diabetes records and gave advice regarding insulin dose adjustment and other problems related to current diabetes therapy. At the end of the trial, participants decided which therapy to continue.