PracticeUpdate Diabetes March 2019

EDITOR’S PICKS 15

Association of Biochemical Hypoglycemia With the Subsequent Risk of a Severe Hypoglycemic Event Diabetes Technology & Therapeutics Take-home message • Although continuous glucose monitoring technology (CGM) has revolutionized diabetes care, some in the research community are hesitant to accept most CGM-derived metrics as evidence for clinical improvement with a device. Even the FDA requires that a study show a reduction in severe hypoglycemia (SH) events, not just overall trends or time spent <70 mg/dL. This study aimed to use data gathered in the Diabetes Control and Complications Trial (DCCT) to evaluate factors associated with SH, as there were higher rates of SH in this cohort. In addition, even though these patients in the DCCT did not use CGM, they were asked to collect a blood sample seven times a day once every 3 months for blood glucose measurement by a central laboratory, providing a large number of data points. This study found that the risk of SH during a 3-month period was substantially higher when there was at least one hypoglycemic blood glucose value in the preceding seven-point profile. This provides evidence that biochemical hypoglycemia at both <70 and <54 mg/dL is associated with a significantly increased risk of SH. • Hopefully, this is the first of many studies evaluating the importance of CGM technology in monitoring for, and reducing the amount of, hypoglycemia events. It would seem that biochemical hypoglycemia is a major risk factor for SH and therefore consideration should be made for adjusting study standards to prove clinical efficacy of a device. In any case, it remains that hypoglycemia is a major risk for people with diabetes using insulin, and healthcare providers should take this into account whenever adjusting a medication regimen. Jason Sloane MD

Abstract OBJECTIVE To evaluate the association of bio- chemical hypoglycemia with subsequent severe hypoglycemia (SH) events using the Diabetes Control and Complications Trial (DCCT) data set. RESEARCH DESIGN AND METHODS The frequency of biochemical hypoglycemia (percentage of values <70 and <54mg/dL [3.9 and 3.0mmol/L) was assessed using DCCT blood glucose con- centrations measured at a central laboratory from seven finger-stick samples (7-point testing: pre- and 90-min postmeals and at bedtime) col- lected during 1 day every 3 months. SH events required a change in mental status necessitating the involvement of another individual to pro- vide treatment. A Poisson model accounting for repeated measures from each participant was used to assess the association of biochemical hypoglycemia frequency, computed from the 7-point finger-stick data, with the development of SH events. RESULTS The risk of SH during a 3-month period was substantially higher (P<0.001) when there was at least one hypoglycemic blood glucose value in the preceding 7-point profile, with technology in monitoring for, and reducing the amount of, hypoglycemia events. " " Hopefully, this is the first of many studies evaluating the importance of CGM

similar results seen for both the 70mg/dL (rate ratio=3.0 [95% confidence interval: 2.6-3.3]) and 54mg/dL (rate ratio=2.7 [95% confidence inter- val: 2.4-3.1]) thresholds. CONCLUSIONS The occurrence of biochemical hypoglycemia <70 or <54mg/dL is associated with an increased risk of SH. For this reason as well as the deleterious effects of hypoglycemia on glucose counter-regulation and hypoglyce- mia awareness, cognition, quality of life, and

arrhythmias, it is important in diabetes manage- ment to avoid hypoglycemic glucose levels as much as possible. The Association of Biochemical Hypoglycemia With the Subsequent Risk of a Severe Hypoglycemic Event: Analysis of the DCCTData Set. Diabetes Technol Ther 2019 Jan 01;21(1)1- 5, RW Beck, RM Bergenstal, TD Riddlesworth, C Kollman. www.practiceupdate.com/c/78238

VOL. 3 • NO. 1 • 2019