Carbohydrate adjusted preprandial insulin doses are supperior to fixed carbohydrate independant insulin doses in slightly overweight people with type 2 diabetes. An evaluation using a Continuous Glucose Monitoring System (CGMS) in addition to Self Monitored Blood Glucose (SMBG)

Abstract

Insulin therapy with a multiple injection regimen (ICT) is often the only means to achieve strict diabetes control in people with type 2 diabetes (T2D). Increasing evidence emphasizes that monitoring postprandial blood glucose (BG) levels is necessary to reduce the cardiovascular risk. Medical advice for adjustment of meal-related insulin doses is often based on anecdotal evidence. Some health care providers recommend fixed (carbohydrate (CHO) independent) meal-related insulin doses, others recommend variable (CHO-dependent) insulin dosage schemes. Aim of this pilot study was to investigate the glucose response of a fixed meal-related Ins dose after different glucose loads and to compare it with the effect of a CHO-adjusted dose. We evaluated 10 T2D patients (mean (m) age 56.4yrs; duration of diabetes 3–6yrs; m BMI 28.3kg/m2; m fasting C-peptide 0.97ng/ml; GAD antibody negative) who were not well controlled on OADs (m HbA1c 7.6%). After initiating of ICT the breakfast(bf)-related insulin (Ins lispro) was titrated to achieve optimal control with a CHO intake of 36 grams (gr) (pre-bf BG <6.1 mmol/l, BG 4 hours after ingestion <6.1, peak postprandial BG <8.9). The next day subjects ingested a bf with 24 gr, the next day a bf with 60 gr CHO always using the initially fixed insulin pre-meal lispro dose. In a subsequent test, subjects used an adjusted insulin dose for the bf with 60 gr CHO. In addition to SMBG we used the CGMS (MiniMed) to evaluate the glucose response to different CHO challenges and insulin doses (results in mg/dl (mmol/l) see table) In summary people with T2D benefit from CHO-adjusted pre-meal insulin doses, especially, with respect to peak postprandial BG levels, which are a major cardiovascular risk factor. The CGMS is a valuable tool to determine the real postprandial peak BG levels, which are often missed by SMBG.