Underestimation of hypoglycaemia using patients' diaries compared with downloaded glucometer data: an ITAS post hoc analysis

Minimizing hypoglycaemia when initiating basal insulin treatment in type 2 diabetes (T2D) is as important as assessing its efficacy in lowering HbA1c. Hypoglycaemic events are often under-reported by people treated with insulin, as indicated by studies comparing the occurrence of hypoglycaemia based on continuous glucose monitoring (CGM) with that based on less comprehensive self-monitored plasma glucose (SMPG).1-3 CGM is not yet routinely used for diabetes management because it is expensive and is not reimbursed in most countries.4 In clinical practice, basal insulin titration is based on daily SMPG with analysis of data downloaded from glucometers. However, people with T2D still commonly present SMPG data that they have entered into their diaries themselves, rather than glucose values directly downloaded from a glucometer. In these circumstances, any retrospective analysis of plasma glucose values is based on data that may contain omissions and mistakes, which may lead to a misestimation of hypoglycaemic events. However, there are currently no reports comparing the incidence or rates of hypoglycaemia based on data downloaded from glucometers with that entered by patients into their diaries. In the Italian Titration Approach Study (ITAS), insulin-naïve people with T2D were initiated to basal insulin treatment with glargine 300 U/mL (Gla-300).5 Insulin was titrated either by the participants themselves, or by physicians using diary data, and resulted in similarly improved glycaemic control and low incidence and rate of hypoglycaemia.5 In ITAS, hypoglycaemia was quantified based on self-reported data from patients' diaries in view of the pragmatic approach of the study. In the current post hoc analysis, to assess whether patients' diaries under-report hypoglycaemia, hypoglycaemia incidence and rates in ITAS were compared using data downloaded from glucometers versus entries from participants' diaries.