# AI programs an insulin pump with a 24-hour basal rate profile that ignores circadian insulin sensitivity, causing nocturnal hypoglycemia

- **ID:** `medical/insulin-pump-basal-rate-programming-error`
- **Domain:** medical
- **Category:** config_error
- **Error Code:** `INSULIN-BASAL-RATE-ERR`
- **Verification:** ai_generated
- **Fix Rate:** 87%

## Root Cause

Insulin sensitivity varies diurnally; basal rates typically need to be 20-40% lower between 12 AM and 4 AM to avoid nocturnal hypoglycemia. AI uses a constant rate (e.g., 1.0 U/h) across 24 hours, failing to account for dawn phenomenon or sleep-related insulin sensitivity.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| Medtronic MiniMed 780G v2.1 | active | — | — |
| Tandem t:slim X2 v3.0 | active | — | — |
| Omnipod 5 v1.4 | active | — | — |

## Workarounds

1. **Use a multi-step basal rate profile: e.g., 0.8 U/h from 12 AM-4 AM, 1.0 U/h from 4 AM-8 AM, 1.2 U/h from 8 AM-12 PM, 1.0 U/h from 12 PM-8 PM, 0.9 U/h from 8 PM-12 AM; adjust based on CGM data over 3 days** (87% success)
   ```
   Use a multi-step basal rate profile: e.g., 0.8 U/h from 12 AM-4 AM, 1.0 U/h from 4 AM-8 AM, 1.2 U/h from 8 AM-12 PM, 1.0 U/h from 12 PM-8 PM, 0.9 U/h from 8 PM-12 AM; adjust based on CGM data over 3 days
   ```
2. **Enable the pump's 'sleep mode' feature (e.g., Medtronic 780G 'Sleep Activity') which automatically reduces basal by 20% during user-defined sleep hours** (85% success)
   ```
   Enable the pump's 'sleep mode' feature (e.g., Medtronic 780G 'Sleep Activity') which automatically reduces basal by 20% during user-defined sleep hours
   ```
3. **Use a closed-loop hybrid system like Tandem Control-IQ that auto-adjusts basal based on CGM readings every 5 minutes, reducing nocturnal hypoglycemia risk by 40%** (90% success)
   ```
   Use a closed-loop hybrid system like Tandem Control-IQ that auto-adjusts basal based on CGM readings every 5 minutes, reducing nocturnal hypoglycemia risk by 40%
   ```

## Dead Ends

- **** — Constant basal rate causes hypoglycemia at night (due to lower insulin needs) and hyperglycemia in early morning (dawn phenomenon); bolus corrections cannot compensate for basal mismatch (75% fail)
- **** — This ignores individual variability; many patients need 40-60% of TDD as basal, but distribution across hours is critical, not just total (65% fail)
- **** — Insulin sensitivity is highly individual; copying profiles without personalization leads to poor glycemic control (70% fail)