What are the goals, targets, and programming considerations for initiating an insulin pump and automated insulin delivery (AID) system in a 16-year-old patient with type 1 diabetes mellitus (T1DM)?

Initiating Insulin Pump and Automated Insulin Delivery in a 16-Year-Old with Type 1 Diabetes

Automated insulin delivery (AID) systems should be the first-line insulin delivery method for this 16-year-old, as they provide superior glycemic control, reduce hypoglycemia risk, and improve quality of life compared to multiple daily injections or non-automated pumps. 1, 2

Glycemic Goals and Targets

A1C and Time-in-Range Targets

• Target A1C <7.0% for most adolescents, though <7.5% is acceptable if hypoglycemia risk is high 2
• Time in range (70-180 mg/dL): >70% of the time 2
• Time below range (<70 mg/dL): <4% and time <54 mg/dL should be <1% 2
• Time above range (>180 mg/dL): <25% 2

These targets are achievable with AID systems, which consistently demonstrate superior A1C reduction and time-in-range improvement compared to multiple daily injections 3, 4

Initial Pump Programming

Total Daily Insulin Dose Calculation

• Start with 0.5-1.0 units/kg/day, with adolescents typically requiring doses toward the higher end (closer to 1.0 units/kg/day) due to pubertal insulin resistance 2
• Split approximately 50% as basal insulin and 50% as bolus insulin 2, 1

Basal Rate Programming

• Divide the total basal dose by 24 hours to establish the initial hourly basal rate 2
• Program multiple basal rates to account for dawn phenomenon (typically increased rates from 3-8 AM) and nocturnal insulin sensitivity 2
• Adjust basal rates in 0.05-0.1 unit/hour increments based on fasting glucose patterns observed over 3-5 days 2

Bolus Settings

• Use rapid-acting insulin analogs exclusively (lispro, aspart, or glulisine) - never use NPH or regular human insulin in pumps 2, 1
• Calculate insulin-to-carbohydrate ratio using the "500 rule": 500 ÷ total daily dose = grams of carbohydrate covered by 1 unit of insulin 2
• Calculate correction factor using the "1800 rule": 1800 ÷ total daily dose = mg/dL drop per 1 unit of insulin 2
• Set active insulin time to 3-4 hours for rapid-acting analogs to prevent insulin stacking 2

AID System Selection and Programming

System Choice Considerations

The American Diabetes Association recommends that choice of AID system should be based on the individual's circumstances, preferences, and needs 1. However, specific considerations include:

• Beta Bionics iLet requires the least technical skill due to minimal user input requirements (only body weight), making it suitable for patients who struggle with carbohydrate counting 3
• Tandem Control-IQ and Omnipod 5 require carbohydrate counting and understanding of insulin-to-carb ratios but offer more user control 3
• All FDA-approved AID systems automatically adjust basal insulin delivery and deliver automatic correction boluses based on CGM values 3

AID-Specific Programming

• AID systems can be initiated at any time, including shortly after diagnosis, and do not require waiting for "better control" on injections 2, 5
• Start with conservative settings initially, then adjust proactively based on downloaded data within 1-2 weeks 2, 5
• Ensure CGM accuracy by proper sensor placement and calibration (if required by the specific system) 3

Essential Patient and Family Education

Core Skills Required Before Initiation

• Carbohydrate counting as the foundation for bolus dosing 2, 5
• Infusion set changes every 2-3 days to prevent site infections and lipohypertrophy 2, 1
• Site rotation across abdomen, thighs, buttocks, and upper arms to prevent lipohypertrophy and erratic insulin absorption 2, 3
• Recognition and management of pump malfunctions, including occlusions, disconnections, and infusion set failures 2, 1

Critical Safety Education

• Risk of rapid development of diabetic ketoacidosis (DKA) with interruption of insulin delivery - patients must have backup supplies and knowledge of how to transition to injections 3, 2
• Meal announcements remain necessary even with the most automated systems - no system is truly "set and forget" 3, 5
• Blood glucose or CGM checks remain essential despite automation 2

Follow-Up Schedule and Adjustments

Initial Follow-Up

• Within 1-2 weeks after pump start to review downloaded data and adjust settings 2
• Focus on basal rate adequacy, bolus patterns, and identification of persistent hyperglycemia or hypoglycemia patterns 2

Ongoing Monitoring

• Every 3 months with A1C measurement 2
• Download pump and CGM data at each visit to assess basal rates, bolus patterns, and glycemic trends 2
• Regular adjustments to AID settings are essential for maintaining effectiveness over time 5

School Accommodation

• The student must be supported at school in using all diabetes technology, including the insulin pump, CGM, and any connected devices as prescribed 2
• A 504 Plan or Individualized Healthcare Plan should be provided to document pump use permissions and ensure appropriate support 2

Common Pitfalls to Avoid

• Do not delay pump initiation waiting for "better control" on injections - AID systems can be started at diagnosis 2, 5
• Do not neglect site rotation - lipohypertrophy and lipoatrophy impair insulin absorption and lead to erratic glucose control 2, 3, 1
• Do not assume monitoring can be eliminated - frequent CGM review and occasional blood glucose checks remain essential 2
• Do not overlook psychosocial factors including anxiety, depression, and diabetes-specific family conflict, as they significantly impact pump success 2, 1
• Do not forget backup supplies - all systems require knowledge of how to transition to injections in case of device failure 3
• Do not ignore CGM accuracy limitations at extreme glucose values during severe hypoglycemia or hyperglycemia, which can affect all AID system performance 3

Evidence Supporting AID as First-Line Therapy

Meta-analyses demonstrate that AID systems are superior to sensor-augmented pump therapy for increased time in range and reduction of hypoglycemia 4, 1. Real-world studies show that second-generation AID systems (advanced hybrid closed-loop) achieve tighter glycemic targets without increased hypoglycemia risk compared to first-generation systems 6. The American Diabetes Association's 2025 guidelines explicitly state that AID systems should be the preferred insulin delivery method for youth and adults with type 1 diabetes who are capable of using the device 1.