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Comparing the performance of different continuous glucose monitoring (CGM) systems is challenging due to the lack of comprehensive guidelines for clinical study design. In particular, the absence of concise requirements for the distribution of comparator (reference) blood glucose (BG) concentrations and their rate of change (RoC), that are used to evaluate CGM performance, impairs comparability. For this article, several experts in the field of CGM performance testing have collaborated to propose characteristics of the distribution of comparator measurements that should be collected during CGM performance testing. Specifically, it is proposed that at least 7.5% of comparator BG concentrations are <70 mg/dL (3.9 mmol/L) and >300 mg/dL (16.7 mmol/L), respectively and that at least 7.5% of BG-RoC combinations indicate fast BG changes with impending hypo- or hyperglycemia, respectively. These proposed characteristics of the comparator data can facilitate the harmonization of testing conditions across different studies and CGM systems and ensure that the most relevant scenarios representing real-life situations are established during performance testing. In addition, a study protocol and testing procedure for the manipulation of glucose levels is suggested that enables the collection of comparator data with these characteristics. This work is an important step towards establishing a future standard for the performance evaluation of CGM systems., The authors thank the Diabetes Center Berne and the International Federation of Clinical Chemistry and Laboratory Medicine for supporting this work.

Aims We aimed to estimate effects of insulin pump therapy (IPT) on HbA1c level, HbA1c variability, and risk of hospitalised diabetic ketoacidosis (DKA) and severe hypoglycaemia (SH), compared with multiple daily insulin injections (MDI). Methods We identified a cohort of all adults with type 1 diabetes in Denmark using national registry data and assigned each individual to either IPT (treatment) or MDI (control) from 2010 to 2020. We estimated average treatment effects on the treated (ATT) and treatment effects among population subgroups using treatment-staggered difference-in-differences. Results The cohort consisted of 26,687 individuals with a collective 243,601 person-years of observation; 38,823 (16 %) were IPT person-years. We identified an ATT for HbA1c of −0.33 % (95 % CI −0.39 to −0.27; −3.6 mmol/mol [95 % CI −4.2 to −2.9]). ATTs were larger among women and individuals who were older, had highest baseline HbA1c, and used continuous glucose monitoring. ATT for HbA1c variability (−0.016 % [−0.028 to −0.0041); −0.17 mmol/mol [95 % CI −0.30 to −0.045]) corresponded to a 6.5 % decrease in the standard deviation of HbA1c. ATTs for DKA and SH corresponded to 0.52 additional and 0.11 fewer hospitalisations per 1,000 person-years, respectively. Conclusions IPT significantly reduced HbA1c level and variability, compared with MDI. However, it also marginally increased the risk of hospitalised DKA., Aims: We aimed to estimate effects of insulin pump therapy (IPT) on HbA1c level, HbA1c variability, and risk of hospitalised diabetic ketoacidosis (DKA) and severe hypoglycaemia (SH), compared with multiple daily insulin injections (MDI).Methods: We identified a cohort of all adults with type 1 diabetes in Denmark using national registry data and assigned each individual to either IPT (treatment) or MDI (control) from 2010 to 2020. We estimated average treatment effects on the treated (ATT) and treatment effects among population subgroups using treatment-staggered difference-in-differences.Results: The cohort consisted of 26,687 individuals with a collective 243,601 person-years of observation; 38,823 (16 %) were IPT person-years. We identified an ATT for HbA1c of-0.33 % (95 % CI-0.39 to-0.27;-3.6 mmol/ mol [95 % CI-4.2 to-2.9]). ATTs were larger among women and individuals who were older, had highest baseline HbA1c, and used continuous glucose monitoring. ATT for HbA1c variability (-0.016 % [-0.028 to-0.0041);-0.17 mmol/mol [95 % CI-0.30 to-0.045]) corresponded to a 6.5 % decrease in the standard deviation of HbA1c. ATTs for DKA and SH corresponded to 0.52 additional and 0.11 fewer hospitalisations per 1,000 person-years, respectively.Conclusions: IPT significantly reduced HbA1c level and variability, compared with MDI. However, it also marginally increased the risk of hospitalised DKA.

Introduction Insulin pump therapy can improve quality of life and glycaemic outcomes for many people with type 1 diabetes (T1D). The multidimensional Steno Tech Survey study aims to investigate why some insulin pump users do not achieve treatment goals. In this article, we present the study design and analyse differences in population characteristics between responders and non-responders. Methods In June 2020, all 1591 insulin pump users (≥ 18 years) in the Capital Region of Denmark were invited to participate in an online questionnaire that evaluated several dimensions of insulin pump self-management and psychosocial health. Demographic, socioeconomic and clinical characteristics, including age, sex and HbA1c, of the cohort were identified via national registries. Predictors of questionnaire response/non-response were explored with logistic regression analysis. Results In the full study population, 58% were female, median age was 42 years and median HbA1c was 58 mmol/mol (7.5%); 30% had HbA1c < 53 mmol/mol (7.0%). In total, 770 individuals (48%) responded to the questionnaire. Logistic regression analysis showed that 50+ years of age (odds ratio [OR] = 2.3, 95% confidence interval [CI]: 1.4–3.8), female sex (OR = 1.3, CI: 1.02–1.6), being married (OR = 1.8, CI: 1.3–2.4) and having long higher education (OR = 1.6, CI: 1.004–2.5) were significantly associated with a higher likelihood of responding to the survey; the opposite was found for HbA1c from 64 to < 75 mmol (8.0–9.0%) (OR = 0.6, CI: 0.4–0.8) and HbA1c ≥ 75 mmol/mol (≥ 9.0%) (OR = 0.2, CI: 0.1–0.3). Conclusions The established Steno Tech cohort enables future analysis of a range of psychosocial and behavioural aspects of insulin pump self-management. Interpretation and generalization of findings should consider observed differences between responders and non-responders.

Aims/hypothesisThis study aimed to compare the increase in plasma glucose after a subcutaneous injection of 200g glucagon given after 45min of cycling with resting (study 1) and to investigate the effects of glucagon when injected before compared with after 45min of cycling (study 2). We hypothesised that: (1) the glucose response to glucagon would be similar after cycling and resting; and (2) giving glucagon before the activity would prevent the exercise-induced fall in blood glucose during exercise and for 2h afterwards.MethodsFourteen insulin-pump-treated individuals with type 1 diabetes completed three visits in a randomised, placebo-controlled, participant-blinded crossover study. They were allocated by sealed envelopes. Baseline values were (mean and range): HbA(1c) 54mmol/mol (43-65mmol/mol) or 7.1% (6.1-8.1%); age 45years (23-66years); BMI 26kg/m(2) (21-30kg/m(2)); and diabetes duration 26years (8-51years). At each visit, participants consumed a standardised breakfast 2h prior to 45min of cycling or resting. A subcutaneous injection of 200g glucagon was given before or after cycling or after resting. The glucose response to glucagon was compared after cycling vs resting (study 1) and before vs after cycling (study 2).ResultsThe glucose response to glucagon was higher after cycling compared with after resting (mean SD incremental peak: 2.61.7 vs 1.82.0mmol/l, p=0.02). As expected, plasma glucose decreased during cycling (-3.1 +/- 2.8mmol/l) but less so when glucagon was given before cycling (-0.9 +/- 2.8mmol/l, p=0.002). The number of individuals reaching glucose values 3.9mmol/l was the same on the 3days.Conclusions/interpretationModerate cycling for 45min did not impair the glucose response to glucagon compared with the glucose response after resting. The glucose fall during cycling was diminished by a pre-exercise injection of 200g glucagon; however, no significant difference was seen in the number of events of hypoglycaemia.Trial registrationThe study was