Analysis of Prevalence, Magnitude and Timing of the Dawn Phenomenon in Adults and Adolescents With Type 1 Diabetes: Descriptive Analysis of 2 Insulin Pump Trials

Automated Insulin Delivery Systems in Pediatric Type 1 Diabetes: A Narrative Review

This narrative review assesses the use of automated insulin delivery (AID) systems in managing persons with type 1 diabetes (PWD) in the pediatric population. It outlines current research, the differences between various AID systems currently on the market and the challenges faced, and discusses potential opportunities for further advancements within this field. Furthermore, the narrative review includes various expert opinions on how different AID systems can be used in the event of challenges with rapidly changing insulin requirements. These include examples, such as during illness with increased or decreased insulin requirements and during physical activity of different intensities or durations. Case descriptions give examples of scenarios with added user-initiated actions depending on the type of AID system used. The authors also discuss how another AID system could have been used in these situations.

Insulin Requirements for Basal and Auto-Correction Insulin Delivery in Advanced Hybrid Closed-Loop System: 4193 Days' Real-World Data of Children in Two Different Age Groups

BACKGROUND

The insulin requirements of people with type 1 diabetes (T1D) can vary throughout the day due to factors such as biorhythm, exercise, and food intake. The MiniMed 780G system delivers micro boluses to adjust basal insulin and delivers auto-correction boluses to meet insulin needs when micro bolus increases are insufficient. Through analysis of MiniMed 780G data, this study investigates the variations in insulin requirements throughout the day.

METHODS

4193 days' pump and continuous glucose monitoring (CGM) data of 34 children using MiniMed 780G were collected from Medtronic CareLink. Micro and auto-correction boluses were analyzed on an hourly basis for two age groups: below nine years old and above nine years old. Glycemic metrics were analyzed based on International CGM consensus.

RESULTS

The mean age was 12.3 years and mean duration of diabetes was 6.1 years. The mean time in range (TIR) and glucose management indicator (GMI) were 80.5% and 6.6%, respectively. The micro bolus (basal) ratio between 05.00 and 07.00 was significantly higher than the ratio between 10.00 and 03.00 (P < .01), whereas micro bolus was significantly lower between 19.00 and 21.00 than those between 00.00 and 10.00 (P < .001). The auto-correction ratio between 21.00 and 00.00 was significantly higher than those between 03.00-17.00 (P < .001) and 19.00-21.00 (P = .008), whereas auto-correction was significantly lower between 07.00 and 10.00 than those between 10.00 and 03.00 (P < .001). The micro bolus ratio was significantly higher in children below nine years old than in children above nine years old between 21.00-00.00 (P = .026) and 00.00-03.00 (P = .003).

CONCLUSION

The basal insulin need follows a diurnal pattern with two significantly different periods-high between 00.00 and 10.00 and low between 10.00 and 00.00. The auto-correction rates are low between 05.00 and 10.00 and show an increasing pattern peaking between 21.00 and 00.00. These findings are compatible with the dawn and reverse dawn phenomena.

Dual-basal-insulin regimen for the management of dawn phenomenon in children with type 1 diabetes: a retrospective cohort study

Background

Handling of the dawn phenomenon (DP) with multiple daily insulin injection (MDII) regimen is a real challenge.

Objective

We aimed to demonstrate the effectiveness of a dual-basal-insulin (a long-acting glargine and an intermediate-acting neutral protamine Hagedorn (NPH)) regimen for the management of DP in children with type 1 diabetes mellitus (T1DM). The primary efficacy outcome was to overcome morning hyperglycemia without causing hypoglycemia during the non-DP period of the night.

Design

Retrospective cohort study.

Method

Charts of 28 children with T1DM (12 female; 42.8%, mean age 13.7 ± 2.1 years) treated with MDII were retrospectively reviewed. The median duration of diabetes was 4.5 years (range 2-13.5 years). DP was diagnosed using a threshold difference of 20 mg/dL (0.1 mmol/L) between fasting capillary blood glucose at 3 a.m. and prebreakfast. NPH was administered at midnight in addition to daily bedtime (08.00-09.00 p.m.) glargine (dual-basal-insulin regimen). Midnight, 03:00 a.m., prebreakfast and postprandial capillary blood glucose readings, insulin-carbohydrate ratios, and basal-bolus insulin doses were recorded the day before the dual-basal-insulin regimen was started and the day after the titration of the insulin doses was complete. Body mass index standard deviation scores (BMI SDS) at the onset-3rd-12th month of treatment were noted.

Results

Before using dual basal insulin, prebreakfast capillary blood glucose levels were greater than those at midnight and at 03:00 a.m. (F = 64.985, p < 0.01). After titration of the dual-basal-insulin doses, there were significant improvements such that there were no statistically significant differences in the capillary blood glucose measurements at the three crucial time points (midnight, 03.00 a.m., and prebreakfast; F = 1.827, p = 0.172). No instances of hypoglycemia were reported, and the total daily insulin per kilogram of body weight did not change. The BMI SDS remained steady over the course of the 1-year follow-up.

Conclusion

In this retrospective cohort study, the dual-basal-insulin regimen, using a long-acting glargine and an intermediate-acting NPH, was effective in overcoming early morning hyperglycemia due to insulin resistance in the DP. However, the effectiveness of the dual-basal-insulin regimen needs to be verified by prospective controlled studies using continuous glucose monitoring metrics or frequent blood glucose monitoring.

Circadian clock, diurnal glucose metabolic rhythm, and dawn phenomenon

The circadian clock provides cue-independent anticipatory signals for diurnal rhythms of baseline glucose levels and glucose tolerance. The central circadian clock is located in the hypothalamic suprachiasmatic nucleus (SCN), which comprises primarily GABAergic neurons. The SCN clock regulates physiological diurnal rhythms of endogenous glucose production (EGP) and hepatic insulin sensitivity through neurohumoral mechanisms. Disruption of the molecular circadian clock is associated with the extended dawn phenomenon (DP) in type 2 diabetes (T2D), referring to hyperglycemia in the early morning without nocturnal hypoglycemia. The DP affects nearly half of patients with diabetes, with poorly defined etiology and a lack of targeted therapy. Here we review neural and secreted factors in physiological diurnal rhythms of glucose metabolism and their pathological implications for the DP.

Improved Nocturnal Glycaemia and Reduced Insulin Use Following Clinical Exercise Trial Participation in Individuals With Type 1 Diabetes

Aim: To explore the influence of clinical exercise trial participation on glycaemia and insulin therapy use in adults with type 1 diabetes (T1D).

Research Design and Methods: This study involved a secondary analysis of data collected from 16 individuals with T1D who completed a randomized clinical trial consisting of 23-h in-patient phases with a 45-min evening bout of moderate intensity continuous exercise. Participants were switched from their usual basal-bolus therapy to ultra-long acting insulin degludec and rapid-acting insulin aspart as well as provided with unblinded interstitial flash-glucose monitoring systems. To assess the impact of clinical trial participation, weekly data obtained at the screening visit (pre-study involvement) were compared against those collated on the last experimental visit (post-study involvement). Interstitial glucose [iG] data were split into distinct glycaemic ranges and stratified into day (06:00–23:59) and night (00:00–05:59) time periods. A p-value of ≤ 0.05 was accepted for significance.

Results: Following study completion, there were significant decreases in both the mean nocturnal iG concentration (Δ-0.9 ± 4.5 mmol.L⁻¹, p < 0.001) and the time spent in severe hyperglycaemia (Δ-7.2 ± 9.8%, p = 0.028) during the night-time period. The total daily (Δ-7.3 ± 8.4 IU, p = 0.003) and basal only (Δ-2.3 ± 3.8 IU, p = 0.033) insulin dose requirements were reduced over the course of study involvement.

Conclusions: Participation in clinical research may foster improved nocturnal glycaemia and reduced insulin therapy use in people with T1D. Recognition of these outcomes may help encourage volunteers to partake in clinical research opportunities for improved diabetes-related health outcomes.

Clinical Trial Registration:DRKS.de; DRKS00013509.