How should automated insulin delivery pumps be adjusted for patients with diabetes (Diabetes Mellitus) who are receiving short courses of steroids as part of their chemotherapy regimen?

Adjusting Automated Insulin Delivery Pumps During Short-Course Steroids in Chemotherapy

For patients on AID systems receiving short courses of steroids during chemotherapy cycles, increase total daily insulin by 50-100% (targeting 1.0-1.3 units/kg/day), distributed as 25-30% basal and 70-75% prandial insulin, with daily titration based on glucose patterns. 1

Immediate Adjustments at Steroid Initiation

Increase total daily insulin dose substantially at the start of each steroid cycle:

• Target 1.0-1.3 units/kg/day total insulin requirement 1
• This represents approximately a 50-100% increase from baseline for most patients
• The distribution should shift toward prandial coverage: 70-75% as bolus/prandial insulin and 25-30% as basal 1

Modify AID system parameters that can be adjusted:

• Increase the glucose target setpoint if your system allows this adjustment 2
• Increase insulin-to-carbohydrate ratios (more aggressive) by 30-50% 1
• Decrease correction factors (more aggressive corrections) by 30-50% 1
• Some systems allow adjustment of "insulin sensitivity factor" - decrease this value to deliver more insulin 2

System-Specific Considerations

For hybrid closed-loop systems (Tandem Control-IQ, Omnipod 5):

• These systems automatically adjust basal insulin but require manual meal boluses 3
• You must manually increase meal bolus doses by 50-100% during steroid cycles 1
• The automated basal adjustments will help but are insufficient alone for steroid-induced hyperglycemia 2

For Beta Bionics iLet (minimal user input system):

• This system makes autonomous dosing decisions with minimal carbohydrate counting 3
• The algorithm should adapt over 2-3 days, but may lag behind rapid steroid-induced insulin resistance 3
• Consider temporarily switching to a system requiring more manual control, or reverting to manual mode if hyperglycemia persists 2

Daily Titration Protocol

Titrate insulin daily during the steroid cycle:

• Review glucose data every 24 hours 1
• If >80% of glucose values remain >250 mg/dL, increase total daily insulin by 20% 1
• If time-in-range (70-180 mg/dL) is <50%, increase insulin by 10-20% 4
• Continue daily adjustments until achieving >60% time-in-range 1

Monitor for hypoglycemia as steroids wear off:

• Hypoglycemia risk increases as steroid effects diminish (typically 12-24 hours after last dose) 1
• In the study of hyper-CVAD patients, only 1.3% of glucose values were <70 mg/dL despite aggressive insulin dosing 1
• The AID system's automatic basal suspension provides some protection, but manual boluses cannot be automatically reduced 2

Cycle-to-Cycle Learning

Use data from previous cycles to preemptively adjust:

• Glucose control improves with subsequent steroid cycles (81% hyperglycemia in first cycle vs 60% in later cycles) 1
• Insulin requirements remain relatively stable across cycles (1.0-1.3 units/kg/day) 1
• Preemptively increase insulin doses at the start of subsequent cycles based on prior cycle requirements 1

Critical Pitfalls to Avoid

Do not rely solely on automated adjustments:

• AID systems are designed for typical day-to-day variability, not the dramatic insulin resistance caused by high-dose steroids 2
• The algorithms will increase insulin delivery, but not rapidly or aggressively enough for steroid-induced hyperglycemia 2
• Manual intervention with increased meal boluses is essential 1

Do not underdose prandial insulin:

• The 70-75% prandial distribution is critical because steroids cause predominantly postprandial hyperglycemia 1
• Standard 50/50 basal-bolus splits are inadequate during steroid therapy 1

Prepare for system reversion:

• Have a backup plan for manual insulin injection therapy if the AID system cannot keep pace with insulin requirements 2
• Stock rapid-acting and long-acting insulin, syringes/pens, and glucose monitoring supplies 2
• Patients may need to temporarily switch to manual mode or open-loop pump therapy 2

Monitoring Intensity

Increase glucose monitoring frequency:

• Check CGM data every 4-6 hours during waking hours 1
• AID systems rely on CGM accuracy, which can be compromised during chemotherapy 2
• Confirm CGM readings with fingerstick glucose if values seem discordant with symptoms 2

Watch for infusion site failures:

• Higher insulin doses increase risk of infusion set occlusion 2, 5
• Change infusion sites every 2 days (rather than 3) during high-dose steroid periods 4
• Unexplained hyperglycemia despite increased insulin settings suggests infusion set failure 2, 5