What are the differences between Beta Bionics (iLet pump), Tandem (t:slim X2 insulin pump with Dexcom continuous glucose monitoring (CGM)) and Twiist insulin pumps for patients requiring insulin pump therapy?

Comparison of Beta Bionics iLet, Tandem t:slim X2, and Twiist Insulin Pumps

All three systems are automated insulin delivery (AID) platforms that should be preferred over non-automated pumps for insulin-deficient diabetes, but they differ substantially in automation level, user input requirements, and form factor. 1

Key Distinguishing Features

Beta Bionics iLet

• Requires minimal user input—only body weight and simple meal announcements (small, medium, large)—with the algorithm making most insulin dosing decisions autonomously 1
• Available in both tubed and tubeless configurations depending on the specific model 1
• Requires the least technical skill and diabetes management knowledge, making it ideal for patients who struggle with carbohydrate counting 1
• No need to program insulin-to-carbohydrate ratios, correction factors, or basal rates 1

Tandem t:slim X2 with Control-IQ

• Uses traditional tubing to deliver insulin through a separate cannula, offering flexibility in pump placement but less discretion 1
• Requires carbohydrate counting for meals and programming of insulin-to-carbohydrate ratios and insulin sensitivity factors 1
• Integrates with Dexcom CGM and automatically adjusts basal insulin delivery and delivers automatic correction boluses when glucose is predicted to rise above 180 mg/dL 1
• Predicts glucose levels 30 minutes in the future, adapting basal rates to maintain glucose between 112.5-160 mg/dL 2
• Significantly reduces fear of hypoglycemia and diabetes-related distress in children, adolescents, and young adults 2
• Requires more diabetes management expertise than iLet but offers more user control 1

Twiist AID

• Provides automated basal rate adjustments when integrated with CGM 1
• Falls between iLet and Tandem in terms of required user expertise 1
• Newer system with less published clinical data compared to the other two platforms 1
• Requires meal announcements for bolus dosing 1

Clinical Evidence and Outcomes

Glycemic Control

• Meta-analyses demonstrate that AID systems reduce A1C by approximately 0.30% compared to multiple daily injections 1
• All AID-capable versions consistently show superior A1C reduction and time-in-range improvement compared to non-automated delivery 1
• Real-world data confirms AID systems reduce total daily insulin requirements while improving glycemic outcomes 1

Hypoglycemia Prevention

• All three systems reduce hypoglycemia risk compared to non-automated insulin delivery 1
• Tandem Control-IQ specifically reduces fear of hypoglycemia in young people and their parents 2
• AID systems provide superior hypoglycemia protection through automatic insulin suspension and predictive algorithms 3

Quality of Life

• Tandem Control-IQ improves sleep quality for both patients and caregivers, though to a lesser extent than other psychological benefits 2
• Diabetes-related distress is decreased with AID systems, leading to better user acceptance 2
• All AID systems allow flexibility in meal timing and content compared to multiple daily injections 3

Patient Selection Algorithm

Choose Beta Bionics iLet when:

• Patient has difficulty with carbohydrate counting or numeracy skills 1
• Lower literacy or technical capability is a concern 3
• Simplicity and minimal user input are priorities 1
• Patient prefers either tubed or tubeless option 1

Choose Tandem t:slim X2 with Control-IQ when:

• Patient is comfortable with carbohydrate counting and diabetes calculations 1
• More user control over insulin dosing is desired 1
• Strong clinical evidence base is important (most published data) 2
• Patient is a child, adolescent, or young adult where psychological outcomes are well-documented 2

Choose Twiist AID when:

• Patient wants moderate automation without extensive carbohydrate counting 1
• Insurance coverage favors this specific manufacturer 1
• Patient falls between the technical skill levels required for iLet and Tandem 1

Critical Pitfalls to Avoid

• Even the most automated systems still require some meal announcements—no system is truly "set and forget" 1
• Failure to rotate infusion sites leads to lipohypertrophy and erratic insulin absorption regardless of pump type 1
• CGM accuracy limitations at extreme glucose values can affect all AID system performance during severe hypoglycemia or hyperglycemia 1
• All systems require backup supplies and knowledge of how to transition to injections in case of device failure 1
• Insurance coverage varies significantly by system and geographic location, with some plans preferring specific manufacturers 1
• Most systems still require manual adjustments for physical activity 4

Common Advantages Across All Three Systems

• Highest time-in-range percentage and lowest time-below-range percentage compared to non-automated delivery 3
• Can deliver insulin in increments of fractions of units 3
• Integration with CGM for automated adjustments 3
• Can adjust basal rates for varying insulin sensitivity by time of day, exercise, and sick days 3
• Superior to sensor-augmented pump therapy for increased time in range and reduction of hypoglycemia 3

Practical Considerations

• All three systems are more expensive than multiple daily injections 3
• Potential reactions to adhesives and site infections can occur with any pump 3
• Most technically complex approach compared to injections, though iLet minimizes this burden 3
• Consistent CGM use is crucial for maximizing benefits of all three systems 4
• Risk of rapid development of ketoacidosis with interruption of insulin delivery applies to all pump systems 3