Pharmacokinetic and Pharmacodynamic Head-to-Head Comparison of Clinical, Equivalent Doses of Insulin Glargine 300 units · mL-1 and Insulin Degludec 100 units · mL-1 in Type 1 Diabetes

Continuous Glucose Monitoring-Derived Glucometrics in Adults with Type 1 Diabetes When Switching Basal Insulins

Context: Limited evidence is available on the real-world effect of insulin degludec (IDeg) in type 1 diabetes (T1D), using continuous glucose monitoring (CGM)-derived metrics. Objective: To assess the real-world effect of switching to IDeg from other long-acting insulins on time in ranges (TIRs) measured by CGM, metabolic control, and insulin dose for people with T1D. Design: This retrospective multicenter study encompassed five time points during a 12-month pre-switch of IDeg and a 12-month follow-up period. For each visit, clinical and CGM data were collected to evaluate temporal trends in glycemic outcomes. Participants: Of 753 persons with T1D who were assessed for eligibility, 486 persons were included, mostly men (61.5%), 47.4 (16.9) years old and diabetes duration of 23.8 (14.2) years at IDeg-initiation. Main Outcome Measure: Primary outcome was the evolution of percent TIR (70-180 mg/dL or 3.9-10.0 mmol/L, TIR) before versus after switch to IDeg. Results: TIR over 24 h increased at 12 months versus baseline (56.7% vs. 52.3%, P < 0.001), mostly during daytime. Time <54 mg/dL (<3.0 mmol/L) over 24 h decreased at 12 months versus baseline (2.02% vs. 2.86%, P < 0.001), mostly during nighttime. Glycated hemoglobin (7.9% vs. 8.1%, P < 0.001) and coefficient of variation (40.0% vs. 41.5%, P < 0.001) improved at 12 months versus baseline. Mean daily basal, bolus and total insulin doses decreased at 12 months (P < 0.001 for all vs. baseline). Conclusions: This retrospective real-world study reports that switching basal insulin significantly improved time spent in glucometric ranges and glycemic variability in the studied population of people with T1D. Clinical Trial Registration number: NCT05434559.

Insulin's Legacy: A Century of Breakthroughs and Innovation

The clinical use of insulin to treat diabetes started just over 100 years ago. The past century has witnessed remarkable innovations in insulin therapy, evolving from animal organ extracts to bioengineered human insulins with ultra-rapid onset or prolonged action. Insulin delivery systems have also progressed to current automated insulin delivery systems. In this review, we discuss the history of insulin and the pharmacology and therapeutic indications for a variety of available insulins, especially newer analog insulins. We highlight recent advances in insulin pump therapy and review evidence on the therapeutic benefits of automated insulin delivery. As with any form of progress, there have been setbacks, and insulin has recently faced an affordability crisis. We address the challenges of insulin accessibility, along with recent progress to improve insulin affordability. Finally, we mention research on glucose-responsive insulins and hepato-preferential insulins that are likely to shape the future of insulin therapy.

Current usage of long-acting insulin analogs in patients with type 2 diabetes mellitus

INTRODUCTION

Insulin treatment is fundamental to diabetes management. Basal insulin therapy reduces intraday glycemic fluctuations upon reaching a steady state. Besides better blood glucose regulation and achieving target HbA1c values in patients, it also offers protection from diabetes complications. In this review, we aimed to compare basal-acting insulins in light of the literature.

AREAS COVERED

We reviewed current evidence related to diabetes treatment with basal insulins. This includes discussions on clinical trials and meta-analyses concerning first and second-generation ultra-long-acting basal insulins. Treatment indications for long-acting basal insulins, which have shown benefits and are considered superior or comparable to others in the literature, are derived from current clinical studies and meta-analyses, which form the basis of the recommendations in this review.

EXPERT OPINION

First and second-generation basal insulins do not show much superiority over each other in terms of blood glucose regulation and reaching the target HbA1c. However, second-generation basal insulins cause fewer hypoglycemic events. We recommend using the appropriate basal insulin in patient-based, individualized treatments. Basal insulin Icodec may become more widely used over time, owing to its association with less hypoglycemia and a reduction in the number of injections.

Insulin Glargine in Type 1 Diabetes Mellitus: A Review of Clinical Trials and Real-world Evidence Across Two Decades

BACKGROUND

Over the past two decades, insulin glargine 100 U/mL (Gla-100) has emerged as the "standard of care" basal insulin for the management of type 1 diabetes mellitus (T1DM). Both formulations, insulin glargine 100 U/mL (Gla-100) and glargine 300 U/mL (Gla- 300) have been extensively studied against various comparator basal insulins across various clinical and real-world studies. In this comprehensive article, we reviewed the evidence on both insulin glargine formulations in T1DM across clinical trials and real-world studies.

METHODS

Evidence in T1DM for Gla-100 and Gla-300 since their approvals in 2000 and 2015, respectively, were reviewed.

RESULTS

Gla-100 when compared to the second-generation basal insulins, Gla-300 and IDeg-100, demonstrated a comparable risk of overall hypoglycemia, but the risk of nocturnal hypoglycemia was higher with Gla-100. Additional benefits of Gla-300 over Gla-100 include a prolonged (>24- hours) duration of action, a more stable glucose-lowering profile, improved treatment satisfaction, and greater flexibility in the dose administration timing.

CONCLUSION

Both glargine formulations are largely comparable to other basal insulins in terms of glucose-lowering properties in T1DM. Further, risk of hypoglycemia is lower with Gla-100 than Neutral Protamine Hagedorn but comparable to insulin detemir.

Diurnal Cycling of Insulin Sensitivity in Type 2 Diabetes: Evidence for Deviation From Physiology at an Early Stage

The aim of this study was to establish the contribution of insulin resistance to the morning (a.m.) versus afternoon (p.m.) lower glucose tolerance of people with type 2 diabetes (T2D). Eleven subjects with T2D (mean [SD] diabetes duration 0.79 [0.23] years, BMI 28.3 [1.8] kg/m2, A1C 6.6% [0.26%] [48.9 (2.9) mmol/mol]), treatment lifestyle modification only) and 11 matched control subjects without diabetes were monitored between 5:00 and 8:00 a.m. and p.m. (in random order) on one occasion (study 1), and on a subsequent occasion, they underwent an isoglycemic clamp (a.m. and p.m., both between 5:00 and 8:00, insulin infusion rate 10 mU/m2/min) (study 2). In study 1, plasma glucose, insulin, C-peptide, and glucagon were higher and insulin clearance lower in subjects with T2D a.m. versus p.m. and versus control subjects (P < 0.05), whereas free fatty acid, glycerol, and β-hydroxybutyrate were lower a.m. versus p.m. However, in study 2 at identical hyperinsulinemia a.m. and p.m. (∼150 pmol/L), glucose Ra and glycerol Ra were both less suppressed a.m. versus p.m. (P < 0.05) in subjects with T2D. In contrast, in control subjects, glucose Ra was more suppressed a.m. versus p.m. Leucine turnover was no different a.m. versus p.m. In conclusion, in subjects with T2D, insulin sensitivity for glucose (liver) and lipid metabolism has diurnal cycles (nadir a.m.) opposite that of control subjects without diabetes already at an early stage, suggesting a marker of T2D.

ARTICLE HIGHLIGHTS

In people with type 2 diabetes (T2D), fasting hyperglycemia is greater in the morning (a.m.) versus the afternoon (p.m.), and insulin sensitivity for glucose and lipid metabolism is lower a.m. versus p.m. This pattern is the reverse of the physiological diurnal cycle of people without diabetes who are more insulin sensitive a.m. versus p.m. These new findings have been observed in the present study in people without obesity but with recent-onset T2D, with good glycemic control, and in the absence of confounding pharmacological treatment. It is likely that the findings represent a specific marker of T2D, possibly present even in prediabetes before biochemical and clinical manifestations.

Continuous glucose monitoring-based time-in-range using insulin glargine 300 units/ml versus insulin degludec 100 units/ml in type 1 diabetes: The head-to-head randomized controlled InRange trial

AIM

To use continuous glucose monitoring (CGM)-based time-in-range (TIR) as a primary efficacy endpoint to compare the second-generation basal insulin (BI) analogues insulin glargine 300 U/ml (Gla-300) and insulin degludec 100 U/ml (IDeg-100) in adults with type 1 diabetes (T1D).

MATERIALS AND METHODS

InRange was a 12-week, multicentre, randomized, active-controlled, parallel-group, open-label study comparing glucose TIR and variability between Gla-300 and IDeg-100 using blinded 20-day CGM profiles. The inclusion criteria consisted of adults with T1D treated with multiple daily injections, using BI once daily and rapid-acting insulin analogues for at least 1 year, with an HbA1c of 7% or higher and of 10% or less at screening.

RESULTS

Overall, 343 participants were randomized: 172 received Gla-300 and 171 IDeg-100. Non-inferiority (10% relative margin) of Gla-300 versus IDeg-100 was shown for the primary endpoint (percentage TIR ≥ 70 to ≤ 180 mg/dl): least squares (LS) mean (95% confidence interval) 52.74% (51.06%, 54.42%) for Gla-300 and 55.09% (53.34%, 56.84%) for IDeg-100; LS mean difference (non-inferiority): 3.16% (0.88%, 5.44%) (non-inferiority P = .0067). Non-inferiority was shown on glucose total coefficient of variation (main secondary endpoint): LS mean 39.91% (39.20%, 40.61%) and 41.22% (40.49%, 41.95%), respectively; LS mean difference (non-inferiority) -5.44% (-6.50%, -4.38%) (non-inferiority P < .0001). Superiority of Gla-300 over IDeg-100 was not shown on TIR. Occurrences of self-measured and CGM-derived hypoglycaemia were comparable between treatment groups. Safety profiles were consistent with known profiles, with no unexpected findings.

CONCLUSIONS

Using clinically relevant CGM metrics, InRange shows that Gla-300 is non-inferior to IDeg-100 in people with T1D, with comparable hypoglycaemia and safety profiles.

Efficacy and safety of basal insulin degludec 100 IU/mL versus glargine 300 IU/mL for type 1 diabetes: The single-center INEOX randomized controlled trial

AIMS

To compare efficacy and safety of degludec 100 IU/mL (Deg-100) and glargine 300 IU/mL (Gla-300) in adults with type 1 diabetes.

METHODS

Open-label, single-center, randomized, parallel-group, 24-week trial in adults with type 1 diabetes, on basal-bolus insulin therapy, HbA1c ≤ 10%, using self-monitoring blood glucose. Participants were randomized 1:1 to a basal-bolus insulin regimen with Deg-100 (N = 129) or Gla-300 (N = 131). Primary efficacy endpoint: mean change in HbA1c from baseline to week-24. Main safety outcome: incidence rate of hypoglycemia during the study. Quality of life (DQOL) and satisfaction with diabetes treatment (DTSQ) were assessed.

RESULTS

At week 24, after adjusting for baseline HbA1c, the decrease in HbA1c did not differ between groups: Deg-100 (-0.07 ± 0.7%) and Gla-300 (-0.16 ± 0.77%) (P = 0.320). There were no significant differences between groups in HbA1c, nocturnal hypoglycemia, severe hypoglycemia, DQOL, or DTSQ scores. The incidence rates of hypoglycemia < 3.9 mmol/L (Deg-100: 115.24 events/person-year vs Gla-300: 99.01 events/person-year, p < 0.001); and < 3.0 mmol/L (Deg-100: 41.17 events/person-year vs Gla-300: 34.29 events/person-year, p < 0.001) were different between groups.

CONCLUSIONS

Deg-100 and Gla-300 have similar metabolic efficacy, incidence ratio of nocturnal and severe hypoglycemia, DQOL and DTSQ scores. Differences in the incidence rate of hypoglycemia < 3.9 mmol/L and < 3.0 mmol/L should be confirmed.

Use of Second-Generation Basal Insulin Gla-300 in Special Populations: A Narrative Mini-Review

BACKGROUND AND AIMS

Hypoglycemia and insulin-related adverse events are crucial barriers to effective diabetes management, particularly in the elderly, people with renal impairment, people with diabetes fasting during Ramadan, or people with type 1 diabetes mellitus (T1DM). There is a scarcity of clinical and real-world evidence assessing the effectiveness and safety of insulin glargine 300 U/mL (Gla-300) in these special populations. To understand the entirety of evidence, this mini-review elaborates on the use of Gla-300 in diabetes management among special populations.

METHODS

Clinical and real-world evidence related to the use of Gla-300 among special populations with diabetes were retrieved using PUBMED and Google Scholar.

RESULTS

Gla-300 has shown improved glycemic control with stable insulin action and low risk of hypoglycemia in diverse groups with diabetes. It also appears to have an acceptable safety profile during Ramadan fasting. However, adequate monitoring and adjustment of insulin dose on an individual basis should be considered.

CONCLUSION

Gla-300 is a second-generation basal insulin with proven benefits of reduced risk of hypoglycemia and improved glycemic control in special populations of people with diabetes.

Insulin: evolution of insulin formulations and their application in clinical practice over 100 years

The first preparation of insulin extracted from a pancreas and made suitable for use in humans after purification was achieved 100 years ago in Toronto, an epoch-making achievement, which has ultimately provided a life-giving treatment for millions of people worldwide. The earliest animal-derived formulations were short-acting and contained many impurities that caused adverse reactions, thereby limiting their therapeutic potential. However, since then, insulin production and purification improved with enhanced technologies, along with a full understanding of the insulin molecule structure. The availability of radio-immunoassays contributed to the unravelling of the physiology of glucose homeostasis, ultimately leading to the adoption of rational models of insulin replacement. The introduction of recombinant DNA technologies has since resulted in the era of both rapid- and long-acting human insulin analogues administered via the subcutaneous route which better mimic the physiology of insulin secretion, leading to the modern basal-bolus regimen. These advances, in combination with improved education and technologies for glucose monitoring, enable people with diabetes to better meet individual glycaemic goals with a lower risk of hypoglycaemia. While the prevalence of diabetes continues to rise globally, it is important to recognise the scientific endeavour that has led to insulin remaining the cornerstone of diabetes management, on the centenary of its first successful use in humans.

Safety, efficacy, and cost-effectiveness of insulin degludec U100 versus insulin glargine U300 in adults with type 1 diabetes: a systematic review and indirect treatment comparison

BACKGROUND

Clinical differences between degludec U100 (Deg-100) and glargine U300 (Gla-300) in type 1 diabetes (T1D) were unknown.

AIM

To indirectly compare the safety, efficacy, and cost-effectiveness between Deg-100 and Gla-300 in T1D adults via systematic review.

METHOD

Medline, the Cochrane Library, ClinicalTrials.gov, and Google Scholar were searched (October 2021). Randomized controlled trials comparing Deg-100 or Gla-300 vs. glargine U100 in T1D adults (follow-up ≥ 12 weeks) were selected and analyzed using a frequentist network meta-analysis. Cost-effectiveness analysis (CEA) was conducted over a 1-year time horizon from societal perspectives.

RESULTS

Nine trials were included. Efficacy analysis suggested that Deg-100 was non-inferior to Gla-300 in reducing HbA_1c (MD 0.03 [95% CI - 0.09 to 0.15]; P = 0.60), FPG (MD - 1.12 [- 2.19 to - 0.04]; P = 0.04), and pre-breakfast SMBG (MD - 0.71 [- 1.46 to 0.03]; P = 0.06). Safety analysis suggested that Deg-100 appeared to have lower rates of both severe (HR 0.44 [0.25-0.78]; P = 0.005) and nocturnal severe (HR 0.19 [0.08-0.44]; P < 0.001) hypoglycemia, with lower total (MD - 0.07 [- 0.13 to - 0.01]; P = 0.02) and basal (MD - 0.08 [- 0.12 to - 0.04]; P < 0.001) insulin doses compared with Gla-300. No significant differences were observed for other hypoglycemia outcomes, adverse events, serious adverse events, bolus insulin dose, and body weight. The CEA showed that Deg-100 appeared to be a dominant treatment in Japan (+ 0.0283 QALYs, ¥26,266 [$228] per patient) and the United States (+ 0.0267 QALYs, $986 per patient).

CONCLUSION

Low-certainty indirect evidence suggested that Deg-100 appeared to have a favorable reduction in rates of severe hypoglycemia and more cost-effective compared with Gla-300 in T1D adults.

Insulin Glargine 300 U/mL Therapy in Children and Adolescents with Type 1 Diabetes

The pharmacokinetic and pharmacodynamic properties of the second-generation basal insulin glargine 300 Units/mL (Gla-300) may be of benefit in the treatment of type 1 diabetes mellitus (T1DM). Gla-300 provides a stable and sustained time-action profile, which is associated with glycaemic control and flexible dosing schedule. This review summarises the available evidence on the safety and efficacy of Gla-300 in children and adolescents with T1DM. Gla-300 is as effective as the first-generation basal insulin glargine 100 Units/mL (Gla-100), a standard of care for patients with diabetes in reducing HbA1c, and shows a lower risk of severe hypoglycaemia and hyperglycaemia in children and adolescents with T1DM. However, Gla-300 and Gla-100 are not bioequivalent and are not directly interchangeable. Real-world studies on patients aged 6-17 years are limited. To date, only one small study assessed the effectiveness and safety of Gla-300 versus Gla-100 in newly diagnosed T1DM paediatric patients, confirming the treatment safety and effectiveness of Gla-300 in clinical practice. Gla-300 is a longer-acting basal insulin alternative in the management of children (aged ≥ 6 years) and adolescents with T1DM.

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.

Establishing target systolic and diastolic blood pressure in diabetic patients with hypertension: what do we need to consider?

INTRODUCTION

The optimum target for systolic and diastolic blood pressure remains divisive. In particular, the conflicting outcomes of the SPRINT and ACCORD trials have led to a divergence of guideline-recommended blood pressure targets for adults with diabetes.

AREAS COVERED

Here, we review the existing recommendations for blood pressure targets in diabetes, discussing the evidence base behind them and their limitations. We start by outlining the risks and benefits of lower systolic blood pressure targets among diabetics. We then follow with a separate appraisal of diastolic blood pressure targets, which necessitates examination of the 'J curve' and isolated diastolic hypertension.

EXPERT OPINION

Current and emerging evidence supports, on balance, a blood pressure therapeutic target of < 130/90 mmHg in adults at increased risk for cardiovascular disease, including diabetics. Whether certain diabetics with systolic BPs of 120-130 and/or diastolic BPs 80-90 mmHg require drug treatment to a target of <120/80 mmHg is less clear and requires more research.

Impact of Socioeconomic Factors and Gender on Refill Adherence and Persistence to Lipid-Lowering Therapy in Type 1 Diabetes

INTRODUCTION

Lipid-lowering therapy (LLT) reduces the risk of cardiovascular disease (CVD) in patients with type 1 diabetes (T1D). However, socioeconomic factors and gender may have an impact on the adherence to and non-persistence with LLT.

METHODS

This was a nationwide register-based cohort study that included 6192 individuals with T1D aged ≥ 18 years who were registered in the Swedish National Diabetes Register and had initiated novel use of LLT. Information on socioeconomic parameters (source: Statistics Sweden) and comorbidity (source: National Patient Register) was collected. The individuals were followed for 36 months, and adherence to LLT was analyzed according to age, socioeconomics and gender. The medication possession ratio (MPR; categorized into ≤ 80% and > 80%) and non-persistence (discontinuation) with medication was calculated after 18 and 36 months.

RESULTS

Individuals older than 53 years were more adherent to LLT (MPR > 80%) than those younger than 36 years (odds ratio [(OR] 1.30, p < 0.0001) at 36 months. Women were more adherent and less prone to discontinue LLT at 18 months (OR 1.05, p = 0.0005 and OR 0.95, p = 0.0004, respectively), but not at 36 months. Divorced individuals were less adherent than married ones (OR 0.93, p = 0.0005) and discontinued LLT more often than the latter (OR 1.06, p = 0.003). Education had no impact on adherence, but individuals with higher incomes discontinued LLT less frequently than those with lower incomes. Individuals with a country of origin other than Sweden discontinued LLT more often.

CONCLUSION

Lower adherence to LLT in individuals with T1D was associated with male gender, younger age, marital status and country of birth. These factors should be considered when evaluating adherence to LLT in clinical practice, with the aim to help patients achieve full cardioprotective treatment.

Glucagon as a Therapeutic Approach to Severe Hypoglycemia: After 100 Years, Is It Still the Antidote of Insulin?

Hypoglycemia represents a dark and tormented side of diabetes mellitus therapy. Patients treated with insulin or drug inducing hypoglycemia, consider hypoglycemia as a harmful element, which leads to their resistance and lack of acceptance of the pathology and relative therapies. Severe hypoglycemia, in itself, is a risk for patients and relatives. The possibility to have novel strategies and scientific knowledge concerning hypoglycemia could represent an enormous benefit. Novel available glucagon formulations, even now, allow clinicians to deal with hypoglycemia differently with respect to past years. Novel scientific evidence leads to advances concerning physiopathological mechanisms that regulated glycemic homeostasis. In this review, we will try to show some of the important aspects of this field.

Glycaemic control and hypoglycaemia risk with insulin glargine 300 U/mL and insulin degludec 100 U/mL in older participants in the BRIGHT trial

AIM

To evaluate the efficacy and safety of insulin glargine 300 U/mL (Gla-300) versus insulin degludec 100 U/mL (IDeg-100) in predefined (</≥65 years) and post hoc (</≥70 years) age groups of people with type 2 diabetes (T2D) in the BRIGHT trial.

MATERIALS AND METHODS

BRIGHT was the first head-to-head randomized trial comparing Gla-300 and Deg-100 in insulin-naïve adults with T2D. In this subanalysis, endpoints were studied by predefined (</≥65 years, N = 596/333) and post hoc (</≥70 years, N = 768/161) age groups.

RESULTS

Heterogeneity of treatment effect was observed for HbA1c reductions across the </≥70 years subgroups, but not across the </≥ 65 years subgroups, with greater HbA1c reductions with Gla-300 versus IDeg-100 in those 70 years or older (least squares mean -0.34% [95% confidence interval: -0.589% to -0.100%]). There was no significant heterogeneity of treatment effect for incidence and rates of confirmed (≤3.9 mmol/L [≤70 mg/dL]) hypoglycaemia across any age subgroups over 24 weeks, but numerically lower incidence and rates were consistently observed for Gla-300 versus IDeg-100 in the 65 years or older and 70 years or older age groups in the initial 12 weeks.

CONCLUSIONS

Gla-300 may be a suitable treatment option in the growing population of older people with T2D. Further investigation is required to determine Gla-300 glycaemic benefits in high-risk populations without increasing the risk of hypoglycaemia.

The physiological basis of insulin therapy in people with diabetes mellitus

Insulin therapy has been in use now for 100 years, but only recently insulin replacement has been based on physiology. The pancreas secretes insulin at continuously variable rates, finely regulated by sensitive arterial glucose sensing. Pancreatic insulin is delivered directlyin the portal blood to insulinize preferentially the liver. In the fasting state, insulin is secreted at a low rate to modulate hepatic glucose output. After liver extraction (50%), insulin concentrations in peripheral plasma are 2.4-4 times lower than in portal, but still efficacious to restrain lipolysis. In the prandial condition, insulin is secreted rapidly in large amounts to increase portal and peripheral concentrations to peaks 10-20 times greater vs the values of fasting within 30-40 min from meal ingestion. The prandial portal hyperinsulinemia fully suppresses hepatic glucose production while peripheral hyperinsulinemia increases glucose utilization, thus limitating the post-prandial plasma glucose elevation. Physiology of insulin indicates that insulin should be replaced in people with diabetes mimicking the pancreas, i.e. in a basal-bolus mode, for fasting and prandial state, respectively. Despite the presently ongoing limitations (subcutaneous and peripheral rather than portal and intravenous insulin delivery), basal-bolus insulin allows people with diabetes to achieve A1c in the range with minimal risk of hypoglycaemia, to prevent vascular complications and to ensure good quality of life.