The Contribution of the Dawn Phenomenon to the Fasting and Post-Breakfast Hyperglycemia in Type 1 Diabetes Treated with Once-Nightly Insulin Glargine
Endocrine Practice, 05/09/2012
King AB et al. – The fasting morning glucose is significantly elevated due to the dawn phenomenon Targeting titration to this glucose may result in excessive basal insulin dosing for the non–dawn phenomenon periods of the day. The dawn phenomenon is a large component of the post–breakfast hyperglycemia. Instead of increasing the morning pre–meal bolus, consideration should be given to pre–treating the earlier dawn phenomenon with an insulin pump using a variable basal insulin rate.Methods
- In 49 subjects on a fixed isocaloric (50% carbohydrate) diet of usual food, insulin glargine dose was titrated from daily continuous glucose monitor, CGM, downloads to achieve a basal glucose goal of <130 mg/dl 4 h after meals and during serial meal omissions but fewer than 10% of readings <70 mg/dl during 24 h.
- Seven point (before and 2 h after each meal or omitted meal and at bedtime) self–monitored plasma glucose (SMPG) testing was also performed.
- The target mean basal glucose was achieved only during the non–dawn phenomenon period (1400 h – 0400 h).
- During the dawn phenomenon the mean basal glucose rose from 118 (57) mg/dl at 0400 h to 156 (67) mg/dl before the breakfast meal, a 32% increase (p = 0.00149).
- The SMPG with meal omission was 63.8% of that increase with a breakfast meal.