The Dawn Phenomenon Revisited: Implications for Diabetes Therapy

Comparing Efficacy of Chiglitazar, Pioglitazone, and Semaglutide in Type 2 Diabetes: A Retrospective Study

INTRODUCTION

Type 2 diabetes (T2D) is a complex chronic metabolic disease characterized by insulin resistance, dyslipidemia, inflammation, and visceral fat accumulation, leading to complications, such as cardiovascular disease and kidney damage. Emerging metabolic regulators, including chiglitazar, semaglutide, and pioglitazone, have gained prominence in managing T2D and associated metabolic disorders. However, their relative efficacy and optimal clinical applications remain unclear. This study's objective was to compare the effects of chiglitazar, semaglutide, and pioglitazone on glycemic control, lipid metabolism, insulin resistance, inflammatory response, liver function, kidney function, and dawn phenomenon intensity in T2D participants, and to explore their relative efficacy and clinical value.

METHODS

This retrospective study was conducted from October 2024 to November 2024 to compare the effects of chiglitazar, semaglutide, and pioglitazone in managing type 2 diabetes (T2D) and associated metabolic disorders.This retrospective cohort study included 175 participants with T2D divided into three groups: chiglitazar (n = 55), semaglutide (n = 57), and pioglitazone (n = 63). participants underwent a 4-week treatment period. Core metrics, including blood glucose, lipid metabolism indicators, urinary albumin-to-creatinine ratio (UACR), and metabolic insulin resistance score (METS-IR), were assessed before and after treatment to evaluate drug efficacy.

RESULTS

Dawn phenomenon: chiglitazar significantly improved dawn phenomenon intensity (Δ0.004 ± 0.80 to -0.77 ± 0.67, p < 0.01), outperforming other drugs. Lipid metabolism: semaglutide demonstrated superior efficacy in reducing total cholesterol (TC) and free fatty acids (FFA) (p < 0.05). Kidney function: both semaglutide and chiglitazar significantly lowered UACR (p < 0.01), with semaglutide showing greater efficacy (-0.13 ± 0.02 versus -0.08 ± 0.01, p < 0.05). Insulin resistance and cardiovascular protection: all three drugs significantly improved METS-IR, with no statistical differences between groups (p > 0.05).

SAFETY

all drugs exhibited good tolerability with no severe adverse events.

CONCLUSIONS

Chiglitazar is particularly effective for participants with pronounced dawn phenomenon, semaglutide excels in lipid metabolism improvement and kidney protection, while pioglitazone remains effective for insulin resistance and glycemic control. These findings provide evidence-based guidance for individualized T2D management.

Evaluation of the Regulatory Effect of the Pan-PPAR Agonist Chiglitazar on the Dawn Phenomenon

INTRODUCTION

The dawn phenomenon (DP), characterized by early morning hyperglycemia, poses a significant challenge in diabetes management and is associated with increased glycemic variability and long-term complications. Despite its clinical impact, effective therapeutic strategies remain limited. Chiglitazar, a novel pan-PPAR agonist, has demonstrated benefits in improving lipid metabolism and insulin sensitivity, but its potential role in mitigating DP remains unexplored. This study evaluates the regulatory effect of chiglitazar on DP and investigates its possible mechanisms beyond lipid modulation.

METHODS

This retrospective observational study included 22 hospitalized diabetic patients who received chiglitazar (20 mg). Blood glucose levels at 3:00 a.m. and fasting glucose levels over three consecutive days were measured pre- and post-treatment, and the dawn phenomenon intensity was calculated. Lipid profiles were assessed to explore potential correlations with glucose changes.

RESULTS

Following chiglitazar administration, significant reductions were observed in LDL-C (43.82 ± 18.27 vs. 36.97 ± 16.90, p < 0.05), FFA (6.00 ± 2.38 vs. 5.06 ± 1.77, p < 0.05), mean 3:00 a.m. blood glucose (Z = - 2.03, p < 0.05), and fasting blood glucose (Z = - 2.96, p < 0.05). DP intensity also significantly improved (Z = - 3.48, p < 0.01). However, no significant correlation was found between glucose improvements and lipid profile changes (p > 0.05), suggesting an alternative mechanism of action.

CONCLUSIONS

Chiglitazar effectively reduces DP intensity and improves glycemic control, independent of its effects on lipid metabolism. These findings suggest a potential link between chiglitazar's mechanism and circadian rhythm regulation, possibly through the modulation of REV-ERB nuclear receptors. Further research is needed to confirm this hypothesis and evaluate the long-term clinical benefits of chiglitazar in diabetes management.

Age-Dependent Bolus Settings: Insulin-to-Carbohydrate Ratios and Insulin Sensitivity Factors in Pediatric Patients with Type 1 Diabetes on Conventional CSII in the DPV Registry

Introduction: Effective bolus settings for insulin-to-carbohydrate ratios (ICRs) and insulin sensitivity factors (ISFs) are crucial for glycemic control in pediatric patients with type 1 diabetes on insulin pumps. Standard calculation methods based on the total daily insulin dose (TDD) often fall short for children. This study examined insulin pump settings for ICR and ISF in pediatric patients, considering diurnal variation, age, sex, and body mass index (BMI). The goal was to provide data-driven recommendations for initial bolus settings. Methods: We analyzed insulin pump settings in 7697 pediatric patients with type 1 diabetes in the DPV registry (Diabetes Prospective Follow-up) from Germany, Austria, Switzerland, and Luxembourg. Patients aged 1 to <18 years, postremission (diabetes duration >1 year, insulin dose ≥0.5 IU/kg/d), with good metabolic control (HbA1c ≤7.5%), using insulin pumps with short-acting analog insulin in 2023, were included. Automated insulin delivery system users were excluded. Patients were grouped by age (<6, 6 to <12, 12 to <18 years), BMI percentiles (P75), and sex. Results: Older children required more insulin, with lower ICRs and ISFs. Insulin requirements peaked in the morning with the lowest ICR and ISF, with medians (interquartile ranges): <6 years: 11.2 g carbs/IU (9.1-14.0) and 1:150 mg/dL (70-228); 6 to <12 years: 8.7 g carbs/IU (7.0-10.7) and 1:90 (50-140); and 12 to <18 years: 6.1 g carbs/IU (5.0-7.7) and 1:50 (40-80). ISF was highest in the late evening in all age groups, while a higher BMI-SDS was associated with a lower ISF. Girls above 6 years had lower ICR but similar ISF to that of boys. The factor obtained by multiplying ISF and TDD was comparable in all age groups and BMI categories. Conclusion: Our real-world findings on CSII settings in a large cohort of children with sufficient metabolic control highlight the inadequacy of a single TDD-based calculation formula, as insulin requirements varied by age, time of day, sex, and BMI. These findings may serve as a reference for commonly used age-dependent parameters for clinicians in establishing initial CSII settings before individualized dose titration and optimization.

Temporal optimization of exercise to lower fasting glucose levels

Exercise stimulates glucose uptake and increases insulin sensitivity acutely. Temporally optimizing exercise timing may minimize the nocturnal rise in glucose levels. This study examined the effect of exercise timing on evening and overnight glucose concentrations in individuals who were non-obese with normal fasting glucose levels (Non-Ob; n = 18) and individuals with obesity (OB) with impaired fasting glucose levels (OB+IFG) and without (n = 16 and n = 18, respectively). Subjects were studied on three occasions (no exercise (NOEX)), morning exercise (AMEX; 0700 h) and evening exercise (PMEX; 2000 h). The evening meal was provided (1800 h) and blood samples were taken from 1740 to 0700 h and morning endogenous glucose production (EGP) was measured. Glucose and insulin concentrations increased with the dinner meal with peak concentrations being higher in OB+IFG than in OB and Non-Ob (P = 0.04). In OB+IFG, evening glucose concentrations rose above baseline levels at about 2300 h, with the glucose concentrations staying somewhat lower with AMEX and PMEX until ∼0500 h than with NOEX. In OB+IFG, insulin concentrations decreased following the dinner meal and waned throughout the night, despite the rising glucose concentrations. In the OB and Non-Ob individuals following the dinner meal, no increase in glucose concentrations occurred in the evening period and insulin levels mirrored this. No difference was observed in the morning fasting glucose levels between study days or between groups. Regardless of time of day, exercise delays the evening rise in glucose concentrations in adults with OB+IFG but does not lower morning fasting glucose levels or improve the synchrony between glucose and insulin concentrations. KEY POINTS: Insulin resistance and type 2 diabetes have been linked to disturbances of the core clock, and glucose tolerance demonstrates a diurnal rhythm in healthy humans with better glucose tolerance in the morning than in the afternoon and evening. Skeletal muscle is a primary site for insulin resistance in people with impaired glucose tolerance. In individuals with obesity and impaired fasting glucose levels (OB+IFG), following a dinner meal, glucose concentrations started to rise and continues throughout the night, resulting in elevated glucose levels, while concomitantly, insulin levels are waning. Exercise, regardless of the time of day, suppressed the rise in glucose levels in OB+IFG for many hours during the night but did not lower morning fasting glucose levels. Morning exercise was not quite as effective as evening exercise.

Treatment Satisfaction With Omnipod DASH in Adults With Type 1 Diabetes: A Nonblinded 1:1 Randomized Controlled Trial

CONTEXT

Omnipod DASH Insulin Management System is a tubeless insulin pump that overcomes the physical inconveniences of conventional tubed insulin pump therapy (IPT).

OBJECTIVE

We compared treatment satisfaction with Omnipod DASH System to usual care (multiple daily injections [MDIs] or tubed IPT) in adults with type 1 diabetes using self-monitoring blood glucose (SMBG).

METHODS

Adults with type 1 diabetes on MDI (n = 40) or IPT (n = 25) from 4 diabetes centers in Australia were randomly assigned in a 1:1 nonblinded manner to Omnipod DASH System (Omnipod group) or continue usual care (Usual Care group) for 12 weeks, followed by a further 12-week extension during which all participants used the device. The primary outcome was treatment satisfaction assessed by change in Diabetes Technology Questionnaire "current" (ΔDTQ-current) score at 12 weeks (study end). Secondary outcomes included ΔDTQ-current following extension and other participant-reported outcomes (PROs) measuring quality of life, burden of disease treatment, and glycemic and device-related outcomes at 12 weeks (study end) and 24 weeks (end extension).

RESULTS

Treatment satisfaction improved more in the Omnipod group vs the Usual Care group (ΔDTQ-current score of 16.4 [21.2] vs 0.0 [12.8]; P < .001) at study end. Significantly greater improvements in other PROs and glycated hemoglobin A1c were also observed. Improvements in DTQ-current and other PROs comparing study end and end extension were similar. While percentage in time in range change from baseline did not differ at study end (-2.0 [12.7] %), it was significantly greater at end extension (5.6 [10.9] %; P = .016).

CONCLUSION

The Omnipod DASH System resulted in greater treatment satisfaction at 12 weeks in adults with type 1 diabetes using SMBG that was sustained after 24 weeks of device use without compromising sleep quality and fear of hypoglycemia. Improvements in glycemia were also observed.

Effect of switching from twice-daily basal insulin to once-daily insulin glargine 300 U/mL (Gla-300) in Brazilian people with type 1 diabetes

BACKGROUND

Low adherence to the number of insulin injections and glycemic variability are among the challenges of insulin therapy in type 1 diabetes (T1D). The TOP1 study investigated the effect of switching from twice-daily (BID) basal insulin to once daily (OD) insulin glargine 300 U/mL (Gla-300) on glycemic control and quality of life.

METHODS

In this 28-week, phase 4 trial, people with T1D aged ≥ 18 years, who were treated with BID basal insulin in combination with prandial rapid-acting insulin for at least 1 year, and had HbA1c between 7.5% and 10.0%, were switched to Gla-300 OD as basal insulin. The present study aimed to evaluate the impact of this change on HbA1c, glycemic profile, treatment satisfaction and safety. The change in HbA1c from baseline to Week 24 was the primary endpoint.

RESULTS

One hundred and twenty-three people with T1D (mean age 37 ± 11 years; 54.5% female) were studied. The disease duration was 20.0 ± 9.8 years, baseline HbA1c and fasting plasma glucose (FPG) were 8.6 ± 0.7% and 201 ± 80.3 mg/dL, respectively. After switching from BID to OD insulin regimen, no significant change in HbA1c was observed from baseline to Week 24 (p = 0.873). There were significant reductions in fasting self-monitoring blood glucose (SMBG) from baseline to Week 24 (175 ± 42 vs. 156 ± 38 mg/dL; p < 0.0001), and in glycemic profile (8-point SMBG) at several time points. There was a significant decrease in the proportion of patients with at least one hypoglycemic event (p = 0.025), in numbers of hypoglycemic events per patient-years of any type (p = 0.036), symptomatic (p = 0.007), and confirmed ≤ 70 mg/dL events (p = 0.049) from run-in to the last 4 weeks on treatment. There were significant improvements in treatment satisfaction (p < 0.0001), perceived hyperglycemia (p < 0.0001) scores and satisfaction with the number of injections between post-run-in and Week 24, and a significant decrease in fear of hypoglycemia.

CONCLUSIONS

Switch from BID basal insulin to OD Gla-300 as part of basal bolus therapy in T1D resulted in similar glycemic control as measured by HbA1c, but provided significant improvements in SMBG, daily glucose profile, a lower incidence of hypoglycemia and increased patient satisfaction.

TRIAL REGISTRATION

NCT03406000.

Insulin degludec in pregestational diabetes: evidence and perspectives

Pregestational diabetes is described when a woman with diabetes before the onset of pregnancy becomes pregnant and consequently she is vulnerable to higher risk for adverse outcomes in the embryo/foetus. Strict glycaemic control, with minimal glucose variability, starting from before conception and maintained throughout pregnancy decreases significantly adverse foetal and maternal outcomes; maternal hypoglycaemic episodes are the major barrier in achieving this goal. Insulin degludec is an ultralong-acting analogue, which has half-life of over 25 h and full duration of effect of more than 42 h, reaching a steady-state serum concentration after 2-3 days of its administration. It promotes flat, steady, peakless and predictable insulin concentrations, with minor intra-individual and inter-individual variability. It also exerts a low mitogenic/metabolic potency ratio. This review examines thoroughly all current evidence of the administration of insulin degludec in pregestational diabetes as well as its future role in this population.

Severe dawn phenomenon predicts long-term risk of all-cause mortality in patients with type 2 diabetes

AIMS

The dawn phenomenon (DP) is an abnormal early morning blood glucose rise without nocturnal hypoglycaemia, which can be more easily and precisely assessed with continuous glucose monitoring (CGM). This prospective study aimed to explore the association between DP and the risk of all-cause mortality in patients with type 2 diabetes.

MATERIALS AND METHODS

A total of 5542 adult inpatients with type 2 diabetes in a single centre were analysed. The magnitude of DP (ΔG) was defined as the increment in the CGM-determined glucose value from nocturnal nadir (after 24:00) to prebreakfast. Participants were stratified into four groups by ΔG: ≤1.11, 1.12-3.33, 3.34-5.55, and >5.55 mmol/L. Cox proportional hazard regression models were used to evaluate the impact of DP on all-cause mortality risk.

RESULTS

During a median follow-up of 9.4 years, 1083 deaths were identified. The restricted cubic spline revealed a nonlinear (p for nonlinearity = 0.002) relationship between ΔG and the risk of all-cause mortality. A multivariate-adjusted Cox regression model including glycated haemoglobin A1c (HbA1c) showed that ΔG > 5.55 mmol/L was associated with 30% (95% CI, 1.01-1.66) higher risk of all-cause mortality, as compared with ΔG 1.12-3.33 mmol/L.

CONCLUSIONS

Higher ΔG is significantly related to an increased risk of all-cause mortality in type 2 diabetes, suggesting that severe DP should be given more attention as a part of glucose management to reduce the risk of long-term adverse outcomes.

"Obviously, Nothing's Gonna Happen in Five Minutes": How Adolescents and Young Adults Infrastructure Resources to Learn Type 1 Diabetes Management

Learning personalized self-management routines is pivotal for people with type 1 diabetes (T1D), particularly early in diagnosis. Context-aware technologies, such as hybrid closed-loop (HCL) insulin pumps, are important tools for diabetes self-management. However, clinicians have observed that practices using these technologies involve significant individual differences. We conducted interviews with 20 adolescents and young adults who use HCL insulin pump systems for managing T1D, and we found that these individuals leverage both technological and non-technological means to maintain situational awareness about their condition. We discuss how these practices serve to infrastructure their self-management routines, including medical treatment, diet, and glucose measurement-monitoring routines. Our study provides insights into adolescents' and young adults' lived experiences of using HCL systems and related technology to manage diabetes, and contributes to a more nuanced understanding of how the HCI community can support the contextualized management of diabetes through technology design.

A probabilistic computation framework to estimate the dawn phenomenon in type 2 diabetes using continuous glucose monitoring

In type 2 diabetes (T2D), the dawn phenomenon is an overnight glucose rise recognized to contribute to overall glycemia and is a potential target for therapeutic intervention. Existing CGM-based approaches do not account for sensor error, which can mask the true extent of the dawn phenomenon. To address this challenge, we developed a probabilistic framework that incorporates sensor error to assign a probability to the occurrence of dawn phenomenon. In contrast, the current approaches label glucose fluctuations as dawn phenomena as a binary yes/no. We compared the proposed probabilistic model with a standard binary model on CGM data from 173 participants (71% female, 87% Hispanic/Latino, 54 ± 12 years, with either a diagnosis of T2D for six months or with an elevated risk of T2D) stratified by HbA1c levels into normal but at risk for T2D, with pre-T2D, or with non-insulin-treated T2D. The probabilistic model revealed a higher dawn phenomenon frequency in T2D [49% (95% CI 37-63%)] compared to pre-T2D [36% (95% CI 31-48%), p = 0.01] and at-risk participants [34% (95% CI 27-39%), p < 0.0001]. While these trends were also found using the binary approach, the probabilistic model identified significantly greater dawn phenomenon frequency than the traditional binary model across all three HbA1c sub-groups (p < 0.0001), indicating its potential to detect the dawn phenomenon earlier across diabetes risk categories.

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.

Akkermansia muciniphila supplementation improves glucose tolerance in intestinal Ffar4 knockout mice during the daily light to dark transition

IMPORTANCE

Alterations in the intestinal environment are associated with various diseases, and FFAR4 is abundantly enriched in the intestine, where it has been shown to have the ability to regulate intestinal hormone secretion and intestinal microbiota; here, we confirmed previous reports. Meanwhile, we found that intestinal FFAR4 regulates glucagon-like peptide 1 secretion by decreasing Akkermansia muciniphila abundance and show that such change is associated with the level of glucose utilization at ZT12 in mice. Intestinal FFAR4 deficiency leads to severely impaired glucose tolerance at the ZT12 moment in mice, and Akkermansia muciniphila supplementation ameliorates the abnormal glucose utilization at the ZT12 moment caused by FFAR4 deficiency, which is very similar to the dawn phenomenon in diabetic patients. Collectively, our data suggest that intestinal Ffar4 deteriorates glucose tolerance at the daily light to dark transition by affecting Akkermansia muciniphila.

Obstructive Sleep Apnea, Circadian Clock Disruption, and Metabolic Consequences

Obstructive sleep apnea (OSA) is a chronic disorder characterized by recurrent episodes of apnea and hypopnea during sleep. It is associated with various cardiovascular and metabolic complications, including type 2 diabetes mellitus (T2DM) and obesity. Many pathways can be responsible for T2DM development in OSA patients, e.g., those related to HIF-1 and SIRT1 expression. Moreover, epigenetic mechanisms, such as miRNA181a or miRNA199, are postulated to play a pivotal role in this link. It has been proven that OSA increases the occurrence of circadian clock disruption, which is also a risk factor for metabolic disease development. Circadian clock disruption impairs the metabolism of glucose, lipids, and the secretion of bile acids. Therefore, OSA-induced circadian clock disruption may be a potential, complex, underlying pathway involved in developing and exacerbating metabolic diseases among OSA patients. The current paper summarizes the available information pertaining to the relationship between OSA and circadian clock disruption in the context of potential mechanisms leading to metabolic disorders.

Insulin settings and their association with time in range in patients with type 1 diabetes users of predictive low glucose suspend (PLGS) augmented insulin pumps in Santiago, Chile

AIMS

Sensor augmented insulin pumps have become a powerful tool for managing type 1 diabetes (T1D). This study aimed to analyze the insulin pump configuration in users of predictive insulin suspension technology (PLGS).

METHODS

T1D patients on insulin pumps with PLGS (Medtronic 640G®) were enrolled. Data was obtained from medical records and pump data was downloaded for 30 days. Basal insulin, bolus calculator parameters, and PLGS operation parameters were analyzed and compared with Time in Range, Time Below Range, and Time Above Range.

RESULTS

112 patients were included, with average TIR of 73,96 % and HbA1c 7,0 % and 25 months of follow-up. Basal insulin remained similar to initial doses, with an increase of 27 % for the Dawn phenomenon. The Carbohydrate ratio was slightly more aggressive. Insulin sensitivity was 17 % less stringent than initially programmed. No differences were observed in Time in Rage according to the number of basal, ratio, and sensitivity segments. Time of insulin suspension correlated directly with Time Bellow Range.

CONCLUSIONS

Patients with good metabolic control have basal insulin programming similar to their initiation doses with less aggressive sensitivity factors. Excessive suspension time determined by PLGS could be an expression of excess insulin and increased hypoglycemia risk.

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.

Diurnal Variation of Real-Life Insulin Sensitivity Factor Among Children and Adolescents With Type 1 Diabetes Using Ultra-Long-Acting Basal Insulin Analogs

BACKGROUND

Estimation of insulin sensitivity factor (ISF) is essential for correction insulin doses calculation. This study aimed to assess real-life ISF among children and adolescents with type 1 diabetes using ultra-long-acting basal insulin analogs and to detect factors associated with ISF among those patients.

METHODS

This prospective observational study was conducted at Sohag University Hospital, Egypt, and included 93 participants aged 6-18 years, diagnosed with T1DM for at least 1 year and using insulin glargine 300 Units/mL or insulin degludec 100 Units/mL as basal insulin. The ISF, insulin-to-carbohydrate ratio (ICR) and insulin doses were initially assessed then adjusted as required. The participants were regularly contacted throughout the follow-up period. Glycemic control parameters were assessed after 3 months.

RESULTS

The ISF showed diurnal variation with higher correction dose requirements for the morning than for the rest of the day (p < 0.001). This pattern of diurnal variation was found in participants with different pubertal stages and in participants using either type of ultra-long acting basal insulin analogs. There was no significant difference between the ISF calculated according to the 1800 rule [1800/Total daily insulin dose (TDD)] and the morning ISF (p = 0.25). The 1800 rule-calculated ISF was significantly lower than the actual ISF for the afternoon (p < 0.001) and the evening (p < 0.001). ISF at different times of the day were significantly correlated with age, body mass index, pubertal stage, diabetes duration, TDD, and ICR. Multiple regression analysis revealed that ICR was the most significant factor associated with ISF. Linear regression analysis revealed that the ISF (in mg/dL) for any time of the day could be estimated as 5.14 × ICR for the same time of the day (coefficient = 5.14, 95% confidence interval: 5.10-5.19, R ² = 0.95, p < 0.001).

CONCLUSION

Diurnal variation of ISF that had to be considered for proper calculation of correction doses. This diurnal variation was found in children and adolescents with different pubertal stages. The 1800 rule was appropriate for the morning correction doses but not in the afternoon or the evening. The TDD and the ICR could be used for ISF estimation.

Meal-time glycaemia in adults with type 1 diabetes using multiple daily injections vs insulin pump therapy following carbohydrate-counting education and bolus calculator provision

AIMS

To compare meal-time glycaemia in adults with type 1 diabetes mellitus (T1D) managed with multiple daily injections (MDI) vs. insulin pump therapy (IPT), using self-monitoring blood glucose (SMBG), following diabetes education.

METHODS

Adults with T1D received carbohydrate-counting education and a bolus calculator: MDI (Roche Aviva Expert) and IPT (pump bolus calculator). All then wore 3-weeks of masked-CGM (Enlite, Medtronic). Meal-times were assessed by two approaches: 1) Set time-blocks (breakfast 06:00-10:00hrs; lunch 11:00-15:00hrs; dinner 17:00-21:00hrs) and 2) Bolus-calculator carbohydrate entries signalling meal commencement. Post-meal masked-CGM time-in-range (TIR) 3.9-10.0 mmol/L was the primary outcome.

RESULTS

MDI(n = 61) and IPT (n = 59) participants were equivalent in age, sex, diabetes duration and HbA1c. Median (IQR) education time provided did not differ (MDI: 1.1 h (0.75, 1.5) vs. IPT: 1.1 h (1.0, 2.0); p = 0.86). Overall, daytime (06:00-24:00hrs), lunch and dinner TIR did not differ for MDI vs. IPT participants but was greater for breakfast with IPT in both analyses with a mean difference of 12.8%, (95 CI 4.8, 20.9); p = 0.002 (time-block analysis).

CONCLUSION

After diabetes education, MDI and IPT use were associated with similar day-time glycemia, though IPT users had significantly greater TIR during the breakfast period. With education, meal-time glucose levels are comparable with use of MDI vs. pumps.

Technological Ecological Momentary Assessment Tools to Study Type 1 Diabetes in Youth: Viewpoint of Methodologies

Type 1 diabetes (T1D) is one of the most common chronic childhood diseases, and its prevalence is rapidly increasing. The management of glucose in T1D is challenging, as youth must consider a myriad of factors when making diabetes care decisions. This task often leads to significant hyperglycemia, hypoglycemia, and glucose variability throughout the day, which have been associated with short- and long-term medical complications. At present, most of what is known about each of these complications and the health behaviors that may lead to them have been uncovered in the clinical setting or in laboratory-based research. However, the tools often used in these settings are limited in their ability to capture the dynamic behaviors, feelings, and physiological changes associated with T1D that fluctuate from moment to moment throughout the day. A better understanding of T1D in daily life could potentially aid in the development of interventions to improve diabetes care and mitigate the negative medical consequences associated with it. Therefore, there is a need to measure repeated, real-time, and real-world features of this disease in youth. This approach is known as ecological momentary assessment (EMA), and it has considerable advantages to in-lab research. Thus, this viewpoint aims to describe EMA tools that have been used to collect data in the daily lives of youth with T1D and discuss studies that explored the nuances of T1D in daily life using these methods. This viewpoint focuses on the following EMA methods: continuous glucose monitoring, actigraphy, ambulatory blood pressure monitoring, personal digital assistants, smartphones, and phone-based systems. The viewpoint also discusses the benefits of using EMA methods to collect important data that might not otherwise be collected in the laboratory and the limitations of each tool, future directions of the field, and possible clinical implications for their use.

A model-based approach to investigating the relationship between glucose-insulin dynamics and dapagliflozin treatment effect in patients with type 2 diabetes

AIMS

To develop a quantitative systems pharmacology model to describe the effect of dapagliflozin (a sodium-glucose co-transporter-2 [SGLT2] inhibitor) on glucose-insulin dynamics in type 2 diabetes mellitus (T2DM) patients, and to identify key determinants of treatment-mediated glycated haemoglobin (HbA1c) reduction.

MATERIALS AND METHODS

Glycaemic control during dapagliflozin treatment was mechanistically characterized by integrating components representing dapagliflozin pharmacokinetics (PK), glucose-insulin homeostasis, renal glucose reabsorption, and HbA1c formation. The model was developed using PK variables, glucose, plasma insulin, and urinary glucose excretion (UGE) from a phase IIa dapagliflozin trial in patients with T2DM (NCT00162305). The model was used to predict dapagliflozin-induced HbA1c reduction; model predictions were compared to actual data from phase III trials (NCT00528879, NCT00683878, NCT00680745 and NCT00673231).

RESULTS

The integrated glucose-insulin-dapagliflozin model successfully described plasma glucose and insulin levels, as well as UGE in response to oral glucose tolerance tests and meal intake. HbA1c reduction was also well predicted. The results show that dapagliflozin-mediated glycaemic control is anticorrelated to steady-state insulin concentration and insulin sensitivity.

CONCLUSIONS

The developed model framework is the first to integrate SGLT2 inhibitor mechanism of action with both short-term glucose-insulin dynamics and long-term glucose control (HbA1c). The results suggest that dapagliflozin treatment is beneficial in patients with inadequate glycaemic control from insulin alone and this benefit increases as insulin control diminishes.

REV-ERB in GABAergic neurons controls diurnal hepatic insulin sensitivity

Systemic insulin sensitivity shows a diurnal rhythm with a peak upon waking1,2. The molecular mechanism that underlies this temporal pattern is unclear. Here we show that the nuclear receptors REV-ERB-α and REV-ERB-β (referred to here as 'REV-ERB') in the GABAergic (γ-aminobutyric acid-producing) neurons in the suprachiasmatic nucleus (SCN) (SCNGABA neurons) control the diurnal rhythm of insulin-mediated suppression of hepatic glucose production in mice, without affecting diurnal eating or locomotor behaviours during regular light-dark cycles. REV-ERB regulates the rhythmic expression of genes that are involved in neurotransmission in the SCN, and modulates the oscillatory firing activity of SCNGABA neurons. Chemogenetic stimulation of SCNGABA neurons at waking leads to glucose intolerance, whereas restoration of the temporal pattern of either SCNGABA neuron firing or REV-ERB expression rescues the time-dependent glucose metabolic phenotype caused by REV-ERB depletion. In individuals with diabetes, an increased level of blood glucose after waking is a defining feature of the 'extended dawn phenomenon'3,4. Patients with type 2 diabetes with the extended dawn phenomenon exhibit a differential temporal pattern of expression of REV-ERB genes compared to patients with type 2 diabetes who do not have the extended dawn phenomenon. These findings provide mechanistic insights into how the central circadian clock regulates the diurnal rhythm of hepatic insulin sensitivity, with implications for our understanding of the extended dawn phenomenon in type 2 diabetes.

Effects of Exercise on Blood Glucose and Glycemic Variability in Type 2 Diabetic Patients with Dawn Phenomenon

Background

The dawn phenomenon (DP) is the primary cause of difficulty in blood glucose management in type 2 diabetic (T2D) patients, and the use of oral hypoglycemic agents has shown weak efficacy in controlling DP. Thus, this study is aimed at investigating the effect of moderate-intensity aerobic exercise before breakfast on the blood glucose level and glycemic variability in T2D patients with DP.

Methods

A total of 20 T2D patients with DP confirmed via continuous glucose monitoring (CGM) participated in the current study. After collecting baseline measurements by CGM as a control, CGM was reinstalled and 30 minutes of moderate-intensity aerobic exercise was performed prior to breakfast. Dawn blood glucose increase, blood glucose levels, and glycemic variability were measured before and after exercise.

Results

Dawn blood glucose increase (ΔGlu, 1.25 ± 0.84vs.2.15 ± 1.07, P = 0.005), highest blood glucose value before breakfast (Gmax, 8.01 ± 1.16vs. 8.78 ± 1.09, P = 0.005), highest blood glucose value before breakfast (Gmax, 8.01 ± 1.16vs. 8.78 ± 1.09, P = 0.005), highest blood glucose value before breakfast (Gmax, 8.01 ± 1.16vs. 8.78 ± 1.09, P = 0.005), highest blood glucose value before breakfast (Gmax, 8.01 ± 1.16vs. 8.78 ± 1.09, P = 0.005), highest blood glucose value before breakfast (Gmax, 8.01 ± 1.16vs.2.15 ± 1.07, P = 0.005), highest blood glucose value before breakfast (Gmax, 8.01 ± 1.16vs.2.15 ± 1.07, P = 0.005), highest blood glucose value before breakfast (Gmax, 8.01 ± 1.16vs.2.15 ± 1.07, P = 0.005), highest blood glucose value before breakfast (Gmax, 8.01 ± 1.16

Conclusions

Acute moderate-intensity aerobic exercise before breakfast reduced the morning rise of blood glucose in T2D patients, partially counteracting DP. Furthermore, exercise significantly reduced blood glucose fluctuations and improved blood glucose control throughout the day. We recommend that T2D patients with DP take moderate-intensity aerobic exercise before breakfast to improve DP and glycemic control.

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

OBJECTIVES

To better understand the dawn phenomenon in type 1 diabetes, we sought to determine its prevalence, timing and magnitude in studies specifically designed to assess basal insulin requirements in patients using insulin pumps.

METHODS

Thirty-three participants from 2 sensor-augmented insulin pump studies were analyzed. Twenty participants were obtained from a methodologically ideal semiautomated basal analysis trial in which basal rates were determined from repeated fasting tests (the derivation set) and 13 from an artificial pancreas trial in which duration of fasting was variable (the "confirmation" set). Prevalence was determined for the total cohort and for individual trials using the standard definition of an increase in insulin exceeding 20% and lasting ≥90 minutes. Among cases, time of onset and percent change in the magnitude of basal delivery were determined.

RESULTS

Seventeen participants (52%) experienced the dawn phenomenon (11 of 20 [55%] in the derivation set and 6 of 13 [46%] in the confirmation set). Time of onset was 3 AM (interquartile range [IQR], 3 to 4:15 AM) in the derivation set and 3 AM (IQR, 3 to 4 AM) in the confirmation set. The magnitude of the dawn phenomenon was a 58.1% (IQR, 28.8% to 110.6%) increase in insulin requirements in the derivation set and 65.5% (IQR, 45.6% to 87.4%) in the confirmation set.

CONCLUSIONS

The dawn phenomenon occurs in approximately half of patients with type 1 diabetes; when present, it has predictable timing of onset (generally 3 AM) and a substantial, but highly variable, magnitude. These findings imply that optimization of glycemic control requires clinical emphasis on fasted overnight basal insulin assessment.

The metabolites NADP+ and NADPH are the targets of the circadian protein Nocturnin (Curled)

Nocturnin (NOCT) is a rhythmically expressed protein that regulates metabolism under the control of circadian clock. It has been proposed that NOCT deadenylates and regulates metabolic enzyme mRNAs. However, in contrast to other deadenylases, purified NOCT lacks the deadenylase activity. To identify the substrate of NOCT, we conducted a mass spectrometry screen and report that NOCT specifically and directly converts the dinucleotide NADP⁺ into NAD⁺ and NADPH into NADH. Further, we demonstrate that the Drosophila NOCT ortholog, Curled, has the same enzymatic activity. We obtained the 2.7 Å crystal structure of the human NOCT•NADPH complex, which revealed that NOCT recognizes the chemically unique ribose-phosphate backbone of the metabolite, placing the 2′-terminal phosphate productively for removal. We provide evidence for NOCT targeting to mitochondria and propose that NADP(H) regulation, which takes place at least in part in mitochondria, establishes the molecular link between circadian clock and metabolism.

Nocturnin is a rhythmically expressed protein that regulates metabolism under the control of circadian clock proposed to function through the deadenylation of metabolic enzyme mRNAs. Here the authors show that Nocturnin and its fly homolog Curled catalyze the removal of 2′-phosphate from NADP⁺ and NADPH, providing a direct link to metabolic regulation.

Improvement of glycemic control by treatment for insomnia with suvorexant in type 2 diabetes mellitus

Introduction

Acute and chronic insomnia can exacerbate type 2 diabetes mellitus (T2DM). We investigated suvorexant (an anti-insomnia drug that targets the orexin system) effects on sleep architecture and glucose metabolism in T2DM patients with insomnia.

Materials and methods

This 7 day open-label, single-arm, intervention trial included 18 subjects with T2DM and insomnia. After 1 day acclimatization, daily glucose levels, sleep architecture, and autonomic nervous function were evaluated by continuous glucose monitoring (CGM), single-channel electroencephalography, and accelerometry, respectively.

Results

Suvorexant treatment for 3 days significantly increased total sleep time and sleep efficiency, with partial suppression of sympathetic nerve activity. CGM-measured 24 h mean glucose level decreased significantly from 157.7 ± 22.9 to 152.3 ± 17.8 mg/dL, especially in the early glucose surge after the midnight nadir (from 28.3 ± 15.0 to 18.2 ± 9.9 mg/dL), and until supper with a significant improvement in homeostasis model assessment of insulin resistance from 4.0 ± 2.8 to 2.9 ± 1.6, respectively.

Conclusions

Suvorexant treatment for insomnia of subjects with T2DM significantly improved CGM-measured daily glycemic control, which was associated with changes in sympathomimetic tone and/or improved insulin sensitivity. The amelioration of insomnia may therefore be a target for improving glycemic control in T2DM patients with insomnia.

Glucagon revisited: Coordinated actions on the liver and kidney

Glucagon secretion is stimulated by a low plasma glucose concentration. By activating glycogenolysis and gluconeogenesis in the liver, glucagon contributes to maintain a normal glycemia. Glucagon secretion is also stimulated by the intake of proteins, and glucagon contributes to amino acid metabolism and nitrogen excretion. Amino acids are used for gluconeogenesis and ureagenesis, two metabolic pathways that are closely associated. Intriguingly, cyclic AMP, the second messenger of glucagon action in the liver, is released into the bloodstream becoming an extracellular messenger. These effects depend not only on glucagon itself but on the actual glucagon/insulin ratio because insulin counteracts glucagon action on the liver. This review revisits the role of glucagon in nitrogen metabolism and in disposal of nitrogen wastes. This role involves coordinated actions of glucagon on the liver and kidney. Glucagon influences the transport of fluid and solutes in the distal tubule and collecting duct, and extracellular cAMP influences proximal tubule reabsorption. These combined effects increase the fractional excretion of urea, sodium, potassium and phosphates. Moreover, the simultaneous actions of glucagon and extracellular cAMP are responsible, at least in part, for the protein-induced rise in glomerular filtration rate that contributes to a more efficient excretion of protein-derived end products.

Views and Experiences of New Zealand Women with Gestational Diabetes in Achieving Glycaemic Control Targets: The Views Study

INTRODUCTION

Optimal glycaemic control in women with gestational diabetes mellitus (GDM) reduces maternal and infant morbidity.

METHOD

A survey was administered to women diagnosed with GDM to explore their views and experiences in achieving optimal glycaemic control.

RESULTS

Sixty women participated. Enablers included being taught to test capillary blood glucose in group settings where the health professional demonstrated this on themselves first (60, 100%); health professionals listening (41, 68%); being reminded to perform blood glucose testing (33, 55%); and being provided healthy meals by friends and family (28, 47%). Barriers included not having information in a woman's first language (33, 55%); being offered unhealthy food (19, 31%); not being believed by health professionals (13, 21%); receiving inconsistent information by health professionals (10, 16%); never being seen twice by the same health professional (8, 13%); and long waiting hours at clinics (7, 11%). Two-thirds of women (37, 62%) reported that food costs were not a barrier, but that they were always or frequently hungry.

CONCLUSION

Optimising experiences for women with GDM for achieving glycaemic control and overcoming barriers, regardless of glycaemic targets, requires further focus on providing meaningful health literacy and support from health professionals, family, friends, and work colleagues.

Interrelationship between 3,5,3´-triiodothyronine and the circadian clock in the rodent heart

Triiodothyronine (T3) is an important modulator of cardiac metabolism and function, often through modulation of gene expression. The cardiomyocyte circadian clock is a transcriptionally based molecular mechanism capable of regulating cardiac processes, in part by modulating responsiveness of the heart to extra-cardiac stimuli/stresses in a time-of-day (TOD)-dependent manner. Although TOD-dependent oscillations in circulating levels of T3 (and its intermediates) have been established, oscillations in T3 sensitivity in the heart is unknown. To investigate the latter possibility, euthyroid male Wistar rats were treated with vehicle or T3 at distinct times of the day, after which induction of known T3 target genes were assessed in the heart (4-h later). The expression of mRNA was assessed by real-time quantitative polymerase chain reaction (qPCR). Here, we report greater T3 induction of transcript levels at the end of the dark phase. Surprisingly, use of cardiomyocyte-specific clock mutant (CCM) mice revealed that TOD-dependent oscillations in T3 sensitivity were independent of this cell autonomous mechanism. Investigation of genes encoding for proteins that affect T3 sensitivity revealed that Dio1, Dio2 and Thrb1 exhibited TOD-dependent variations in the heart, while Thra1 and Thra2 did not. Of these, Dio1 and Thrb1 were increased in the heart at the end of the dark phase. Interestingly, we observed that T3 acutely altered the expression of core clock components (e.g. Bmal1) in the rat heart. To investigate this further, rats were injected with a single dose of T3, after which expression of clock genes was interrogated at 3-h intervals over the subsequent 24-h period. These studies revealed robust effects of T3 on oscillations of both core clock components and clock-controlled genes. In summary, the current study exposed TOD-dependent sensitivity to T3 in the heart and its effects in the circadian clock genes expression.

Rebound hyperglycaemia in diabetic cats

OBJECTIVES

Rebound hyperglycaemia (also termed Somogyi effect) is defined as hyperglycaemia caused by the release of counter-regulatory hormones in response to insulin-induced hypoglycaemia, and is widely believed to be common in diabetic cats. However, studies in human diabetic patients over the past quarter century have rejected the common occurrence of this phenomenon. Therefore, we evaluated the occurrence and prevalence of rebound hyperglycaemia in diabetic cats.

METHODS

In a retrospective study, 10,767 blood glucose curves of 55 cats treated with glargine using an intensive blood glucose regulation protocol with a median of five blood glucose measurements per day were evaluated for evidence of rebound hyperglycaemic events, defined in two different ways (with and without an insulin resistance component).

RESULTS

While biochemical hypoglycaemia occurred frequently, blood glucose curves consistent with rebound hyperglycaemia with insulin resistance was confined to four single events in four different cats. In 14/55 cats (25%), a median of 1.5% (range 0.32-7.7%) of blood glucose curves were consistent with rebound hyperglycaemia without an insulin resistance component; this represented 0.42% of blood glucose curves in both affected and unaffected cats.

CONCLUSIONS AND RELEVANCE

We conclude that despite the frequent occurrence of biochemical hypoglycaemia, rebound hyperglycaemia is rare in cats treated with glargine on a protocol aimed at tight glycaemic control. For glargine-treated cats, insulin dose should not be reduced when there is hyperglycaemia in the absence of biochemical or clinical evidence of hypoglycaemia.

Performance and safety of an integrated bihormonal artificial pancreas for fully automated glucose control at home

AIMS

To assess the performance and safety of an integrated bihormonal artificial pancreas system consisting of one wearable device and two wireless glucose sensor transmitters during short-term daily use at home.

METHODS

Adult patients with type 1 diabetes using an insulin pump were invited to enrol in this randomized crossover study. Treatment with the artificial pancreas started with a day and night in the clinical research centre, followed by 3 days at home. The control period consisted of 4 days of insulin pump therapy at home with blinded continuous glucose monitoring for data collection. Days 2-4 were predefined as the analysis period, with median glucose as the primary outcome.

RESULTS

A total of 10 patients completed the study. The median [interquartile range (IQR)] glucose level was similar for the two treatments [7.3 (7.0-7.6) mmol/l for the artificial pancreas vs. 7.7 (7.0-9.0) mmol/l for the control; p = 0.123]. The median (IQR) percentage of time spent in euglycaemia (3.9-10 mmol/l) was longer during use of the artificial pancreas [84.7 (82.2-87.8)% for the artificial pancreas vs. 68.5 (57.9-83.6)% for the control; p = 0.007]. Time in hypoglycaemia was 1.3 (0.2-3.2)% for the artificial pancreas and 2.4 (0.4-10.3)% for the control treatment (p = 0.139). Separate analysis of daytime and night-time showed that the improvements were mainly achieved during the night.

CONCLUSIONS

The results of this pilot study suggest that our integrated artificial pancreas provides better glucose control than insulin pump therapy in patients with type 1 diabetes at home and that the treatment is safe.

Near normal HbA1c with stable glucose homeostasis: the ultimate target/aim of diabetes therapy

Achieving near normal glucose homeostasis implies that all components of dysglycemia that are present in diabetes states be eliminated. Reducing ambient/overall hyperglycemia is a pre-requisite to eliminate the risk of development and progression of diabetes complications. More controversially however, are the relative and related contributions of postprandial glucose excursions, glucose variability, hypoglycemia and the dawn phenomenon across the spectrum of dysglycemia. For instance, it is likely that the dawn phenomenon contributes to ambient hyperglycemia and that postprandial glucose excursions are at the cross road of ambient hyperglycemia and glucose variability with glucose fluctuations as causative risk factors for hypoglycemia. Proof-of-concept trials such as the ongoing FLAT-SUGAR study are necessary for gaining further insight into the possible harmful effects of some of these features such as excessive glycemic variability and glucose excursions, still considered to be of minor relevance by several diabetologists. Whether their role will be more thoroughly proven through further intervention trials with "hard" endpoints, remains to be seen. In the meantime more consideration should be given to medications aimed at concomitantly reducing ambient/overall hyperglycemia and those additional abnormal glycemic features of dysglycemia.

In-Silico Trials for Glucose Control in Hospitalized Patients with Type 2 Diabetes

Although various basal-bolus insulin therapy (BBIT) protocols have been used in the clinical environment, safer and more effective BBIT protocols are required for glucose control in hospitalized patients with type 2 diabetes (T2D). Modeling approaches could provide an evaluation environment for developing the optimal BBIT protocol prior to clinical trials at low cost and without risk of danger. In this study, an in-silico model was proposed to evaluate subcutaneous BBIT protocols in hospitalized patients with T2D. The proposed model was validated by comparing the BBIT protocol and sliding-scale insulin therapy (SSIT) protocol. The model was utilized for in-silico trials to compare the protocols of adjusting basal-insulin dose (BBIT1) versus adjusting total-daily-insulin dose (BBIT2). The model was also used to evaluate two different initial total-daily-insulin doses for various levels of renal function. The BBIT outcomes were superior to those of SSIT, which is consistent with earlier studies. BBIT2 also outperformed BBIT1, producing a decreased daily mean glucose level and longer time-in-target-range. Moreover, with a standard dose, the overall daily mean glucose levels reached the target range faster than with a reduced-dose for all degrees of renal function. The in-silico studies demonstrated several significant findings, including that the adjustment of total-daily-insulin dose is more effective than changes to basal-insulin dose alone. This research represents a first step toward the eventual development of an advanced model for evaluating various BBIT protocols.

The Effects of Transition from Bedtime to Morning Glargine Administration in Patients with Poorly Regulated Type 1 Diabetes Mellitus: Croatian Pilot Study

INTRODUCTION

The objective of this study was to compare differences in glucoregulation, frequency of hypoglycemic episodes, glucose variability and lipid profiles of inpatients with poorly regulated type 1 diabetes mellitus (T1DM) after evening versus morning glargine application.

METHODS

Eighteen patients with poorly regulated T1DM, glycated hemoglobin (Hba1c) levels ≥7% and frequent nocturnal and/or morning hypoglycemic episodes were included in this study. There was a 12-week screening phase where patients continued their usual insulin regimen and were encouraged to achieve optimal glycemic control; however, all patients maintained HbA1c values ≥7% and continued to have frequent nocturnal and/or morning hypoglycemic events and were therefore transitioned to morning application of insulin glargine for 12 weeks. The primary outcome was to investigate changes in HbA1c values 12 weeks after the transition. The secondary outcome was to evaluate the effect of transition on glucose variability, incidence of hypoglycemic episodes, insulin doses, lipid profile and weight. Data were analyzed using paired Student's t test and Pearson correlation.

RESULTS

After the transition, there was no significant change in total daily dose of basal insulin (p 0.114) and the average body weight remained unchanged, while significant reduction of HbA1c was present (8.02 ± 0.5 vs. 7.4 ± 0.3%) (p < 0.01) resulting in a decrease in nocturnal and daytime hypoglycemic episodes per month per person (p < 0.01). Parameters of glucose variability (glycemic standard deviations and J-index) were also improved after transition period (p < 0.01). As for the lipid profile, increase of high-density lipoprotein cholesterol and decrease of triglycerides (p < 0.01) were noticed, while other lipid parameters remained unaffected. Furthermore, insignificant association of basal insulin dose with HbA1c values regardless of the time of administration was observed.

CONCLUSION

In patients with poorly regulated T1DM, transition to morning application of glargine improved glucoregulation (including a decrease in HbA1c, glucose variability and number of nocturnal hypoglycemic episodes), followed by favorable changes in lipid profile without affecting body weight. These effects were associated with the time of application, but not with the insulin dose.

"Mild dysglycemia" in type 2 diabetes: to be neglected or not?

"Mild dysglycemia" in type 2 diabetes can be defined by the range of HbA1c levels≥6.5% (48 mmol/mol) and<7% (53 mmol/mol), which corresponds to when the risk for vascular complications begins to increase. This "mild dysglycemia" is characterized by both a dawn phenomenon (a spontaneous blood glucose rise in the early morning) and an excess of post-prandial glucose excursions in the absence of abnormal elevation in basal glucose, especially during nocturnal periods. This represents an intermediary stage between pre-diabetes (HbA1c≥5.7%, 39 mmol/mol, and<6.5%, 48 mmol/mol) and those who begin to show a steadily progressive worsening in basal glucose (HbA1c≥7%, 53 mmol/mol). Should this relatively minor intermediate dysglycemic phase deserve more attention, that is the question. The now available incretin-based therapies, and more specifically the DPP-4 inhibitors provide the clinician with the possibility to reduce or eradicate both the dawn phenomenon and post-meal glucose excursions with minimal side effects. The availability of 24-h glycemic profiles in those with "mild dysglycemia" will help to describe their individual glycemic phenotype, based on which the early and appropriate life style changes and/or pharmacological interventions can be introduced.

The Effectiveness and Risks of Programming an Insulin Pump to Counteract the Dawn Phenomenon in Type 1 Diabetes

OBJECTIVE

Continuous subcutaneous insulin infusion (CSII) programming for an early morning increase in insulin delivery is frequently recommended to counteract the rise in glucose prior to breakfast (dawn phenomenon). However, both the effectiveness and safety of this approach have not been tested in the ambulatory setting. Using continuous glucose monitoring, we investigated the safety and effectiveness of early morning CSII programming for management of the dawn phenomenon in subjects with type 1 diabetes.

METHODS

We conducted a controlled, observational eight-month longitudinal study of type 1 diabetic patients (n=40). Reproducibility of the dawn phenomenon was determined in subjects treated with multiple daily injections of insulin (MDI, n=12) and those on CSII who did not program an early morning increase in insulin delivery (CSII non-programmers, n=8). The effects of early morning CSII programming were determined by comparing rates of the dawn phenomenon and hypoglycemia in CSII non-programmers versus CSII-users who programmed an early morning increase in insulin delivery (CSII programmers, n=20).

RESULTS

The dawn phenomenon occurred in all tested subjects to a variable extent (median rate 56% of nights). CSII programming was not associated with a reduction in the occurrence of the dawn phenomenon (42%) compared to non-programmers (48%) (P=0.47) nor in the magnitude of the dawn phenomenon. Hypoglycemia occurred more frequently in the CSII programmers (37%) compared to non-programmers (18%) (P=0.001).

CONCLUSION

The dawn phenomenon occurs unpredictably; therefore, early morning CSII programming for a fixed increase in early morning insulin delivery is ineffective and may be hazardous to the patient.

Closed-loop artificial pancreas systems: physiological input to enhance next-generation devices

To provide an understanding of both the preclinical and clinical aspects of closed-loop artificial pancreas systems, we provide a discussion of this topic as part of this two-part Bench to Clinic narrative. Here, the Bench narrative provides an in-depth understanding of insulin-glucose-glucagon physiology in conditions that mimic the free-living situation to the extent possible in type 1 diabetes that will help refine and improve future closed-loop system algorithms. In the Clinic narrative, Doyle and colleagues compare and evaluate technology used in current closed-loop studies to gain further momentum toward outpatient trials and eventual approval for widespread use.

Glucose variability before and after treatment of a patient with Graves' disease complicated by diabetes mellitus: assessment by continuous glucose monitoring

A 48-year-old woman was diagnosed and treated for Graves' disease (GD) in 1999 but she discontinued treatment at her own discretion. In 2011, she was admitted to a local hospital for management of thyrotoxic crisis. Treatment with propylthiouracil, iodide potassium (KI), and prednisolone (PSL) was started, which resulted in improvement of the general condition. PSL and KI were discontinued before she was transferred to our hospital. At the local hospital, fasting plasma glucose (FPG) was 212 mg/dL and hemoglobin A1c concentration was 11.2%; intensive insulin therapy had been instituted. Upon admission to our hospital, FPG level was 122 mg/dL, but insulin secretion was compromised, suggesting aggravation of thyroid function and deterioration of glycemic control. The FPG level increased to 173 mg/dL; continuous glucose monitoring (CGM) identified dawn phenomenon at approximately 0400 h. Resumption of KI resulted in improvement of FPG and disappearance of the dawn phenomenon, as assessed by CGM. These results indicate that in patients with compromised insulin secretion, hyperthyroidism can induce elevation of not only postprandial blood glucose, but also FPG level due to the dawn phenomenon and that the dawn phenomenon can be alleviated with improvement in thyroid function. To our knowledge, no studies have assessed glucose variability by CGM before and after treatment of Graves' disease. The observations made in this case shed light on the understanding of abnormal glucose metabolism associated with Graves' disease.

Magnitude of the dawn phenomenon and its impact on the overall glucose exposure in type 2 diabetes: is this of concern?

OBJECTIVE

To assess the magnitude of the dawn phenomenon and its impact on the total glucose exposure in type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 248 noninsulin-treated persons with type 2 diabetes who underwent continuous glucose monitoring were divided into three groups selected by treatments: diet alone (n = 53); insulin sensitizers alone (n = 82); and insulin secretagogues alone or in combination with insulin sensitizers (n = 113). The dawn phenomenon (∂ glucose, mg/dL) was quantified by its absolute increment from nocturnal nadir to prebreakfast value. The participants were secondarily divided into two paired subsets after they had been separated by the presence/absence of a dawn phenomenon based on a threshold of 20 mg/dL and matched for glucose nadir. The impact of the dawn phenomenon was assessed on HbA1c and 24-h mean glucose.

RESULTS

The median of ∂ glucose (interquartile range) was 16.0 (0-31.5 mg/dL) in the 248 subjects, and no differences were observed across groups selected by HbA1c or treatments. In the overall population, the mean impacts on HbA1c and 24-h mean glucose were 4.3 ± 1.3 mmol/mol (0.39 ± 0.12%) and 12.4 ± 2.4 mg/dL, respectively. The mean impact on 24-h mean glucose was not statistically different between those on diet alone (16.7 ± 5.9 mg/dL) compared with the two subsets treated with oral hypoglycemic agents (11.2 ± 5.3 and 8.5 ± 7.5 mg/dL).

CONCLUSIONS

The impact of the dawn phenomenon on overall glycemic control in type 2 diabetes, as depicted by the HbA1c level, was ∼0.4% and not eliminated by any of the currently available armamentarium of oral antidiabetes agents.

The relationship between estimated average glucose and fasting plasma glucose

BACKGROUND

Estimated average glucose (eAG) is a value calculated from hemoglobin A1c (HbA1c) that reflects average glycemic status over the preceding few months. A linear relationship between HbA1c and eAG was demonstrated by the International HbA1c-Derived Average Glucose (ADAG) Trial in 2008. We investigated the relationship between fasting plasma glucose (FPG) and eAG.

METHODS

This retrospective study was conducted by reviewing the medical records of 6443 subjects, including 5567 diabetic patients and 876 non-diabetic subjects. The levels of HbA1c and FPG were reviewed and eAG was calculated using the regression equation published by the ADAG trial: eAGmmol/L=1.59×HbA1c(NGSP, %)-2.59[eAGmg/dL= 28.7×HbA1c(NGSP, %)-46.7].

RESULTS

In all subjects, FPG showed a moderate correlation with eAG (r=0.672, p<0.001). When diabetic and non-diabetic subjects were divided into subgroups according to FPG level, the correlation between eAG and FPG decreased in both diabetic [FPG ≥10.0 mmol/L (180 mg/dL), r=0.425; FPG 7.2-9.9 mmol/L (130-179 mg/dL), r=0.373; FPG <7.2 mmol/L (130 mg/dL), r=0.202] and non-diabetic [FPG 5.6-6.9 mmol/L (100-125 mg/dL), r=0.363; FPG <5.6 mmol/L (100 mg/dL), r=0.186] subgroups as the FPG level decreased. The differences between eAG and FPG were statistically significant (p<0.001). Only 81% (4487/5567) of diabetic patients had a lower FPG level than eAG level.

CONCLUSIONS

Our results suggest that the relationship between eAG and FPG may depend on glycemic control, thereby enhancing our understanding of eAG.

Effect of growth hormone on dawn phenomenon in patients with type 2 diabetes

We aimed to investigate the involvement of growth hormone in dawn phenomenon and insulin sensitivity in patients with type 2 diabetes mellitus (T2DM). On six occasions separated by intervals of at least 3 days, subjects received early evening (16:00 hours) or late night (23:00 hours) pretreatment with subcutaneous injection of normal saline, human growth hormone, or octreotide. Modified euglycemic insulin clamp test was done 16 hours later and variable glucose infusion (M values) was determined. Plasma glucose, serum insulin, insulin-like growth factor-1, non-esterified fatty acids, and metabolic clearance rate of insulin (MCRI) were measured. Early evening application of growth hormone decreased MCRI 16 hours later, suggesting reduction in insulin sensitivity. Exogenous growth hormone injection reduced insulin sensitivity in T2DM patients. Results provide direct evidence for the role of growth hormone in regulating the insulin sensitivity in insulin-resistant patients.

Frequency and severity of the dawn phenomenon in type 2 diabetes: relationship to age

OBJECTIVE

To know whether age has an independent effect on the dawn phenomenon in noninsulin-using type 2 diabetes.

RESEARCH DESIGN AND METHODS

Eighty-one individuals with type 2 diabetes were matched for HbA(1c) and divided by age into three subgroups of 27 individuals (1: ≥70 years; 2: 60-69 years; and 3: ≤59 years). All underwent ambulatory continuous glucose monitoring for quantifying the dawn phenomenon (i.e., the absolute [∂G, mg/dL] or relative [∂G%] increments from nocturnal nadirs to prebreakfast time points).

RESULTS

HbA(1c) levels and 24-h glycemic profiles were similar across the three groups. Glucose increments (mean ± SEM) were identical in the three groups: ∂G (mg/dL), 22.0 ± 4.7 (1), 21.3 ± 3.6 (2), and 18.0 ± 3.6 (3) and δG (%), 19.9 ± 4.9 (1), 21.6 ± 4.4 (2), and 17.6 ± 4.2 (3). Using the most common definition (∂G >10 mg/dL), the prevalence of the dawn phenomenon was 52, 70, and 59% in groups 1, 2, and 3, respectively.

CONCLUSIONS

The dawn phenomenon is present in the elderly.

Insulin pump dosing across gestation in women with well-controlled type 1 diabetes mellitus

OBJECTIVE

We hypothesized that bolus and basal insulin doses in women with type 1 diabetes mellitus who use insulin pumps would increase 2-fold to maintain hemoglobin A1c <6.5% across gestation.

STUDY DESIGN

This was a retrospective study of 9 women with type 1 diabetes mellitus with preconceptional hemoglobin A1c ≤ 7.4% using insulin pumps. The primary outcome was absolute and percentage change of basal and bolus insulin from preconception to delivery.

RESULTS

Total daily dose of insulin increased from 33.3 ± 7.8 U/d before conception to 93.5 ± 27.9 U/d at delivery. Basal rates rose modestly (50% increase, from 16.2 ± 6.5 U/d to 24.0 ± 9 U/d); bolus insulin doses quadrupled from 17.1 ± 6.1 U/d to 69.5 ± 29.6 U/d (P = .0001). Bolus insulin increased from approximately 50% of total daily dose of insulin before conception to 75% of total daily dose of insulin at 36 weeks' gestation.

CONCLUSION

In well-controlled type 1 diabetes mellitus, insulin requirements increased 3-fold from before conception to 36 weeks' gestation. Most of this requirement was attributed to an increase in bolus rates that are required for control with meals.

Control of type 1 diabetes mellitus and shift work

BACKGROUND

People with type 1 diabetes may find diabetic control more difficult when working shifts.

AIMS

To investigate the proportion of people with type 1 diabetes in employment undertaking shift work and diabetic control as assessed by glycosylated haemoglobin (HbA1c) among individuals undertaking shift work compared to those not doing so.

METHODS

A postal questionnaire sent to all those aged 16-65 attending two city hospitals for type 1 diabetes care. HbA1c results were used to assess diabetic control.

RESULTS

Twenty-two per cent (296 of 1370 eligible patients) responded. Sixty-seven (23%) respondents were involved in shift work. Shift workers had higher mean HbA1c values than non-shift workers (9.02 versus 8.35; P < 0.01).

CONCLUSIONS

Poorer control of diabetes was associated with working shifts in this study. Occupational health practitioners should be aware of this association and be able to advise on management strategies to improve diabetic control while working shifts.

Insulin doses before and one year after pump start: children have a reversed dawn phenomenon

OBJECTIVE

We aimed to investigate the basal rate and bolus doses in children and adolescents at the start of insulin pump therapy and after 1 year of use.

PATIENTS AND METHODS

Case records from 29 children and adolescents were examined. All pumps were started with rapid-acting insulin (Humalog). Patients were aged 13.1 ± 3.9 years, with a diabetes duration of 5.4 ± 4.1 years at pump start. Sixteen pumps were started for high hemoglobin A1c (HbA1c; >8.8%, 73 mmol/mol) and 13 for other reasons.

RESULTS

Basal rates declined in both groups by 20% at 3 days after pump start. The bolus doses were reduced by 25-30% when the indication was high HbA1c and by 15% in the others. After 1 year, there was a significant difference in the basal rate between age groups. The 3-9-year-old age group had higher basal rates during the late evening (10:00 PM-12:00 AM), while the 15-21-year-old age group had higher basal rates in the early morning (3:00 AM-7:00 AM).

CONCLUSIONS

Insulin doses are reduced considerably when starting with a pump in pediatric practice. Younger children needed higher basal rates late in the evening (reversed dawn phenomenon), while older teenagers seem to need an increase in the morning, which may correspond to a true dawn phenomenon.

Closed-loop insulin delivery in type 1 diabetes

Advances in diabetes technology have led to significant improvements in the quality of life and care received by individuals with diabetes. Despite this, achieving tight glycemic control through intensive insulin therapy and modern insulin regimens is challenging because of the barrier of hypoglycemia, the most feared complication of insulin therapy as reported by patients, caregivers, and physicians. This article outlines the individual components of the closed-loop system together with the existing clinical evidence. The artificial pancreas prototypes currently used in clinical studies are reviewed as well as obstacles and limitations facing the technology.