The choice of the insulin basal rate regimen at initiation of insulin pump therapy in routine clinical practice

Background: Numbers of patients with diabetes mellitus using insulin pumps have been increasing every year. Successful achievement of glycemic targets with continuous subcutaneous insulin infusion (CSII) is based on an adequate basal rate of infusion, carbohydrate coefficient and insulin sensitivity index. There are two approaches to basal insulin infusion rate, namely the flat one and the circadian; however, at present there is no convincing data on which one should be chosen at the start of insulin pump therapy.Aim: To compare two regimens of basal insulin infusion rate at initiation of insulin pump therapy in routine clinical practice.Materials and methods: We analyzed data from 120 patients with Type 1 diabetes mellitus, who were switched on insulin pump therapy in the Department of Endocrinology from 2017 to 2018. At initiation of CSII, 60 patients used the flat basal rate profile and the other 60 patients used the circadian basal rate, calculated with the Renner's scale. Safety of the two basal rate regimens was assessed based on glucose variability measured with continuous glucose monitoring during the first two days after the start of insulin pump therapy.Results: Mean (± SD) coefficients of variation in the groups with circadian and flat basal rate at Day 1 were 31.06±12.13 and 32.74±10.7, respectively (p=0.423); at Day 2, 26.78±11.27 and 28.83±10.7 (p=0.309). Median [Q1; Q3] areas under glucose curve (AUC) values above the glucose targets in the groups with circadian and flat basal rate at Day 1 were 0.37 [0.03; 0.89] and 0.48 [0.08; 1.75], respectively, at Day 2 0.44 [0.03; 1.57] and 0.31 [0.1; 1.5], respectively (p>0.05). Median glucose AUC values below the goal in groups with circadian basal rate and flat basal rate on the first day were 0.01 [0; 0.06] and 0.02 [0; 0.1], respectively (p=0.855), on the second day – 0.00 [0; 0.01] and 0.00 [0; 0.02], respectively (р=0.085). We also haven’t found any between-group differences in the prevalence of glucose deviations below and above the target, as well as in the time spent in normoglycaemia.Conclusion: The comparative analysis of two basal insulin rate regimens in Type 1 diabetic patients switched to insulin pump therapy has shown no significant differences between them. The use of Renner’s scale has no clinical advantages over the fixed basal insulin regimen at initiation of insulin pump therapy in adults.

Description of a Novel Patch Pump for Insulin Delivery and Comparative Accuracy Evaluation

A new insulin patch pump for continuous subcutaneous insulin infusion was developed. The pump is composed of reusable and disposable parts and operates with a stepping motor. This pump was compared to a patch pump and a durable pump regarding basal rate and bolus accuracy. Using a microgravimetric method, boluses of 0.2 U, 1 U and 7 U, and a basal rate of 1 U/h were tested. For all pumps, bolus accuracy was higher when larger volumes were delivered. While median deviations were similar for all pumps, there were differences in the precision of individual boluses and when regarding basal rate delivery divided into 1-h windows.

Carbohydrate Requirements for Prolonged, Fasted Exercise with and without Basal Rate Reductions in Adults with Type 1 Diabetes on Continuous Subcutaneous Insulin Infusion (CSII)

<b>Objective:</b> Exercising while fasted in type 1 diabetes facilitates weight loss, however the best strategy to maintain glucose stability remains unclear. <p><b>Research Design and Methods:</b> Fifteen adults on CSII completed three sessions of fasted walking (120min at 45%VO_2peak) in a randomized crossover design: 50% basal rate reduction set 90min pre-exercise (-90_min50%_BRR); usual basal rate with carbohydrate intake (0.3g/kg/hr; CHO-only); and combined 50%basal rate reduction set at exercise onset with carbohydrate (0.3g/kg/hr; Combo). </p> <p><b>Results:</b> Combo had a smaller change in glucose (5±47mg/dL) vs CHO-only (-49±61mg/dL, <i>P</i>=0.03) or -90_min50%_BRR (-34±45mg/dL). -90_min50%_BRR produced higher b-hydroxybutyrate levels (0.4±0.3 vs 0.1±0.1mmol/L) and greater fat oxidation (0.51±0.2 vs 0.39±0.1g/min) than CHO-only (both <i>P</i><0.05).</p> <b>Conclusions:</b> All strategies examined produced stable glycemia for fasted exercise, but a 50%basal rate reduction set 90 min pre-exercise eliminates carbohydrate needs and enhances fat oxidation better than carbohydrate feeding with or without a basal rate reduction set at exercise onset.

Carbohydrate Requirements for Prolonged, Fasted Exercise with and without Basal Rate Reductions in Adults with Type 1 Diabetes on Continuous Subcutaneous Insulin Infusion (CSII)

<b>Objective:</b> Exercising while fasted in type 1 diabetes facilitates weight loss, however the best strategy to maintain glucose stability remains unclear. <p><b>Research Design and Methods:</b> Fifteen adults on CSII completed three sessions of fasted walking (120min at 45%VO_2peak) in a randomized crossover design: 50% basal rate reduction set 90min pre-exercise (-90_min50%_BRR); usual basal rate with carbohydrate intake (0.3g/kg/hr; CHO-only); and combined 50%basal rate reduction set at exercise onset with carbohydrate (0.3g/kg/hr; Combo). </p> <p><b>Results:</b> Combo had a smaller change in glucose (5±47mg/dL) vs CHO-only (-49±61mg/dL, <i>P</i>=0.03) or -90_min50%_BRR (-34±45mg/dL). -90_min50%_BRR produced higher b-hydroxybutyrate levels (0.4±0.3 vs 0.1±0.1mmol/L) and greater fat oxidation (0.51±0.2 vs 0.39±0.1g/min) than CHO-only (both <i>P</i><0.05).</p> <b>Conclusions:</b> All strategies examined produced stable glycemia for fasted exercise, but a 50%basal rate reduction set 90 min pre-exercise eliminates carbohydrate needs and enhances fat oxidation better than carbohydrate feeding with or without a basal rate reduction set at exercise onset.

Prediction of Individual Basal Rate Profiles From Patient Characteristics in Type 1 Diabetes on Insulin Pump Therapy

Background: Basal rate profiles in patients with type 1 diabetes on insulin pump therapy are subject to enormous inter-individual heterogeneity. Tools to predict basal rates based on clinical characteristics may facilitate insulin pump therapy. Methods: Data from 339 consecutive in-patients with adult type 1 diabetes on insulin pump therapy were collected. Basal rate tests were performed over 24 hours. A mathematical algorithm to predict individual basal rate profiles was generated by relating the individual insulin demand to selected clinical characteristics in an exploratory cohort of 170 patients. The predicted insulin pump profiles were validated in a confirmatory cohort of 169 patients. Findings: Basal rates (0.27 ± 0.01 IU.d−1.kg−1) showed circadian variations with peaks corresponding to the “dawn” and “dusk” phenomena. Age, gender, duration of pump treatment, body-mass-index, HbA1c, and triacylglycerol concentrations largely predicted the individual basal insulin demand per day (IU/d; exploratory vs prospective cohorts: r2 = 0.518, P < .0001). Model-predicted and actual basal insulin rates were not different (exploratory cohort: Δ 0.1 (95% CI −0.9; 1.0 U/d; P = .95; prospective cohort: Δ −0.5 (95% CI −1.5; 0.6 IU/d; P = .46). Similarly, precise predictions were possible for each hour of the day. Actual and predicted “dawn” index correlated significantly in the exploratory but not in the confirmatory cohort. Interpretation: Clinical characteristics predict 52% of the variation in individual basal rate profiles, including their diurnal fluctuations. The multivariate regression model can be used to initiate or optimize insulin pump treatment in patients with type 1 diabetes.

Adjustment of Insulin Pump Settings in Type 1 Diabetes Management: Advisor Pro Device Compared to Physicians’ Recommendations

Aims: To compare insulin dose adjustments made by physicians to those made by an artificial intelligence-based decision support system, the Advisor Pro, in people with type 1 diabetes (T1D) using an insulin pump and self-monitoring blood glucose (SMBG). Methods: This was a multinational, non-interventional study surveying 17 physicians from 11 countries. Each physician was asked to provide insulin dose adjustments for the settings of the pump including basal rate, carbohydrate-to-insulin ratios (CRs), and correction factors (CFs) for 15 data sets of pumps and SMBG of people with T1D (mean age 18.4 ± 4.8 years; eight females; mean glycated hemoglobin 8.2% ± 1.4% [66 ± 11mmol/mol]). The recommendations were compared among the physicians and between the physicians and the Advisor Pro. The study endpoint was the percentage of comparison points for which there was an agreement on the direction of insulin dose adjustments. Results: The percentage (mean ± SD) of agreement among the physicians on the direction of insulin pump dose adjustments was 51.8% ± 9.2%, 54.2% ± 6.4%, and 49.8% ± 11.6% for the basal, CR, and CF, respectively. The automated recommendations of the Advisor Pro on the direction of insulin dose adjustments were comparable )49.5% ± 6.4%, 55.3% ± 8.7%, and 47.6% ± 14.4% for the basal rate, CR, and CF, respectively( and noninferior to those provided by physicians. The mean absolute difference in magnitude of change between physicians was 17.1% ± 13.1%, 14.6% ± 8.4%, and 23.9% ± 18.6% for the basal, CR, and CF, respectively, and comparable to the Advisor Pro 11.7% ± 9.7%, 10.1% ± 4.5%, and 25.5% ± 19.5%, respectively, significant for basal and CR. Conclusions: Considerable differences in the recommendations for changes in insulin dosing were observed among physicians. Since automated recommendations by the Advisor Pro were similar to those given by physicians, it could be considered a useful tool to manage T1D.