24-hour blood glucose profiles in insulin-dependent diabetics treated with intravenous insulin infusion systems. A comparison between closed- and open-loop systems

Three months use of Hybrid Closed Loop Systems improves glycated hemoglobin levels in adolescents and children with type 1 diabetes: A meta-analysis

BACKGROUND

Longer outpatient studies have demonstrated that hybrid closed loop (HCL) use has led to a concomitant reduction in glycated hemoglobin(HbA1c) by 0.3%-0.7%. However, reports have also indicated that HbA1c levels are not declined in the long-term use of HCL. Therefore, we wonder that 3 months use of HCL could improve glycated hemoglobin levels in adolescents and children with T1D.

METHODS

Relevant studies were searched electronically in the Cochrane Library, PubMed, and Embase utilizing the key words "Pediatrics or Child or Adolescent", "Insulin Infusion Systems" and "Diabetes Mellitus" from inception to 17th March 2024 to evaluate the performance of HCL on HbA1c in adolescents, and children with T1D.

RESULTS

Nine studies involving 927 patients were identified. Three months use of HCL show a beneficial effect on HbA1c management (p <0.001) as compared to standard of care in adolescents and children with T1D, without evidence of heterogeneity between articles (I2 = 40%, p = 0.10). HCL did significantly increase the overall average percentage of hypoglycemic time between 70 and 180 mg/dL (TIR) (p <0.001; I2 = 51%). HCL did not show a beneficial effect on hypoglycemic time <70 mg/dL and <54 mg/dL (p >0.05). The overall percentage of hyperglycemic time was significantly decreased in HCL group compared to the control group when it was defined as >180 mg/dL (p <0.001; I2 = 83%), >250 mg/dL (p = 0.007, I2 = 86%) and >300 mg/dL (p = 0.005; I2 = 76%). The mean glucose level was significantly decreased by HCL (p <0.001; I2 = 58%), however, no significant difference was found in coefficient of variation of sensor glucose (p = 0.82; I2 = 71%) and daily insulin dose (p = 0.94; I2 <0.001) between the HCL group and the control group.

CONCLUSIONS

HCL had a beneficial effect on HbA1c management and TIR without increased hypoglycemic time as compared to standard of care in adolescents and children with T1D when therapy duration of HCL was not less than three months.

TRIAL NUMBER AND REGISTRY URL

CRD42022367493; https://www.crd.york.ac.uk/PROSPERO, Principal investigator: Zhen-feng Zhou, Date of registration: October 30, 2022.

Automated insulin delivery in children with type 1 diabetes during physical activity: a meta-analysis

OBJECTIVES

The aim of this study was to evaluate the performance of the automated insulin delivery (AID) in adolescents, and children with type 1 diabetes (T1D) during physical activity.

METHODS

Relevant studies were searched electronically in the Cochrane Library, PubMed, and Embase utilizing the key words "Child", "Insulin Infusion Systems", and "Diabetes Mellitus" from inception to 17th March 2024 to evaluate the performance of the AID in adolescents, and children with T1D during physical activity.

RESULTS

Twelve studies involving 514 patients were identified. AID did not show a beneficial effect on duration of hypoglycemia<70 mg/dL during study period (p>0.05; I2=96 %) and during the physical activity (p>0.99). Percentage of sensor glucose values in TIR was higher in AID than the non-AID pumps during study period (p<0.001; I2=94 %). The duration of hyperglycemic time was significantly decreased in AID group compared to the non-AID pumps group during study period (p<0.05; I2>50 %).

CONCLUSIONS

AID improved TIR and decreased the duration of hyperglycemic time, but did not appear to have a significant beneficial effect on the already low post-exercise duration of hypoglycemia achievable by open loop or sensor-augmented pumps in adolescents and children with T1D during physical activity; further research is needed to confirm the beneficial effect of AID on duration of hypoglycemia.

Effects of insulin on renal haemodynamics and sodium handling in normal subjects

Diabetic patients treated with insulin injected subcutaneously are characterized by peripheral hyperinsulinaemia and an increased mass of total body exchangeable sodium. We hypothesized that this may cause, at least in part, the glomerular hyperfiltration seen in the diabetic state. Six normal subjects were studied on 2 days in random order. Day A: Basal state for 40 min, hyperinsulinaemic euglycaemic clamp for 1 h (insulin infusion rate 2 mU kg-1 min-1 and 50% glucose infusion) and hyperinsulinaemic euglycaemic clamp combined with volume expansion (2 1 isotonic sodium chloride) for 2 h. Day B: as day A, but without insulin and glucose infusion. During combined volume expansion and hyperinsulinaemia an increase in glomerular filtration rate (GFR) (128 +/- 6 vs 117 +/- 8 ml min-1 1.73 m-2, p less than 0.01) and lithium clearance (CLi) (50 +/- 4 vs 33 +/- 5 ml min-1 1.73 m-2, p less than 0.01) was observed compared with basal conditions. GFR and CLi were unchanged during day B. Insulin infusion reduced renal sodium excretion. Absolute proximal tubular reabsorption was unchanged on both days. Insulin infusion without volume expansion caused a decrease of 24% in the fractional distal sodium excretion. Superimposed volume expansion and the concomitant increase in GFR and CLi was accompanied by a subsequent enhanced fractional distal sodium excretion of 27%. The changes in plasma concentrations of aldosterone, renin, angiotensin II, atrial natriuretic peptide and catecholamines did not explain the differences in GFR. An increase in GFR of 10%, comparable with that observed in diabetic patients, was induced by combined hyperinsulinaemia and volume expansion in euglycaemic normal subjects. The enhanced GFR is probably a compensatory response to the sodium retention induced by the action of insulin on the distal tubules.

Importance of early postprandial insulin delivery in insulin-dependent diabetics

In nine insulin-dependent diabetics postprandial glucose control under closed loop insulin infusion by an artificial endocrine pancreas was compared with that obtained under open loop infusion employing identical infusion profiles which were advanced 20 min by time in the case of open loop infusion. The earlier increase of insulin infusion rates in the latter case resulted in lower postprandial glucose concentrations during the first 90 min after meal intake. Incremental areas under the blood glucose curves during this time were significantly lower when insulin infusion rates rose earlier (4.5 X 10(3) +/- 0.5 X 10(3) vs 2.1 X 10(3) +/- 0.6 X 10(3) mg/dl X min; p less than 0.02). Insulin was administered at maximum rates 45-50 min after the start of the meal during closed loop infusion (196 +/- 38 mU/min) and 25-30 min after the meal during open loop infusion (192 +/- 35 mU/min). Correspondingly, mean free insulin concentrations which are available from six patients rose to 135 +/- 47 (40 min) or 141 +/- 50 muU/ml (20 min). Glucagon levels did not differ between both parts of the study. It is concluded that increases of postprandial insulin infusion rates occurring earlier than increases of blood glucose levels are important for optimizing glucose profiles and possibly reflect physiologic conditions.

Absorption of NPH-insulin from subcutaneous tissue: a methodological study in pigs

To elucidate the validity of the indirect method of following insulin absorption from the subcutaneous tissue, i.e. external counting of injected 125-I insulin, the disappearance of 125-I NPH insulin from subcutaneous tissue was measured by a biotelemetric method (external measurement of radioactivity) and by direct determination of radioactivity and insulin in subcutaneous tissue extracted one to 300 min. after injection of 8 units 125-I NPH porcine insulin, 5 mm beneath the surface of the skin in 6 anaesthesized pigs. Furthermore, the appearance of insulin in arterial plasma was measured after inhibiting the endogenous insulin secretion of the pigs by epinephrine and propanolol. The disappearance of radioactivity measured continuously for 5 hours was of first order kinetics with t1/2=462+/-36 min. (mean+/-S.E.M.). The half-life of the injected depot of radioactivity (t1/2) demonstrated a large intra- as well as interindividual variation as seen in diabetics. In tissue extracts a highly significant (2P less than 0.001) correlation was found between radioactivity and insulin (r=0.93), indicating the radioactivity to be representative of insulin. During gel chromatography on Sephadex G 50 M only one peak of radioactivity was seen in all tissue extracts. 300 min. after NPH-insulin injection, however, the specific radioactivity of insulin was significantly higher (2P less than 0.05) than in tissue extracts sampled one min. after NPH insulin injection, indicating a slight accumulation of non-immunoreactive insulin degradation products. A fair correlation (r=0.75, 2 P less than 0.05) was seen between the disappearance of externally measured radioactivity or insulin from tissue extracts and the appearance of insulin in plasma. It is concluded that the insulin absorption coefficient is a relevant and biologically sensible expression of insulin absorption.