For a patient using a Tandem insulin pump with basal rates of 1.45 U/h at 12 AM, 1.00 U/h at 2 AM, 1.20 U/h at 6 AM, 1.70 U/h at 8 AM, and 1.50 U/h at 9 PM, an insulin‑to‑correction factor of 1 unit per 8 mg/dL, and a time‑in‑range of 54% with frequent hyperglycemia, what adjustments to basal rates or correction factor would improve time‑in‑range?

Increase Basal Rates and Strengthen Correction Factor

With a TIR of only 54% and frequent hyperglycemia, you need to increase your basal insulin rates across all time blocks and strengthen your correction factor from 1:8 to 1:5 or 1:6 mg/dL. Your current settings are insufficient to maintain euglycemia, and the correction factor is too weak to effectively bring down elevated glucose levels 1, 2.

Immediate Adjustments Needed

Basal Rate Increases

Your basal rates should be increased by 10-20% across all time periods to address the persistent hyperglycemia 1, 2, 3. Based on your current settings:

• 12:00 AM: Increase from 1.45 to 1.60-1.75 U/h
• 2:00 AM: Increase from 1.00 to 1.10-1.20 U/h
• 6:00 AM: Increase from 1.20 to 1.35-1.45 U/h
• 8:00 AM: Increase from 1.70 to 1.90-2.05 U/h (dawn phenomenon period needs aggressive coverage)
• 9:00 PM: Increase from 1.50 to 1.65-1.80 U/h

The early morning hours (6:00-8:00 AM) likely need the most aggressive increases given the dawn phenomenon, where counter-regulatory hormones drive glucose elevation 4, 5.

Correction Factor Adjustment

Change your insulin sensitivity factor from 1:8 to 1:5 or 1:6 mg/dL 1, 2. This means:

• Current: 1 unit drops glucose by 8 mg/dL
• New: 1 unit should drop glucose by 5-6 mg/dL

This stronger correction factor will more effectively address hyperglycemic excursions throughout the day.

Adjustment Strategy

Systematic Titration Approach

1. Make changes every 2-3 days based on glucose patterns 1, 2
2. Adjust one time block at a time to identify which periods need the most correction
3. Focus first on overnight/fasting periods (12 AM-8 AM) since basal rates are most accurately assessed when not influenced by meal boluses 5, 6
4. Monitor for 3-5 days after each adjustment before making further changes

Specific Time Block Analysis

• Overnight (12 AM-6 AM): If fasting glucose rises during these hours, increase basal rates by 0.1-0.2 U/h increments 5
• Dawn period (6 AM-8 AM): This typically requires 15-25% higher basal rates than other periods 5, 7
• Daytime (8 AM-9 PM): Adjust based on glucose trends between meals when no bolus insulin is active 2

Critical Considerations

Avoid Overbasalization

While you need increases, monitor for signs of overbasalization 3:

• Total basal dose exceeding 0.5 units/kg/day
• Large bedtime-to-morning glucose differentials
• Hypoglycemia episodes
• High glycemic variability

If these occur, the problem may be inadequate meal boluses rather than insufficient basal insulin.

Correction Factor Testing

The correction factor should consistently bring glucose into target range within 3-4 hours 1, 2. If corrections repeatedly fail to normalize glucose, strengthen the factor further (move toward 1:5 or even 1:4 if needed in insulin-resistant patients).

Meal Bolus Consideration

With 54% TIR and frequent hyperglycemia, also verify your insulin-to-carbohydrate ratio (ICR) is appropriate 1, 2. If post-meal glucose consistently exceeds target by 2-3 hours, your ICR may also need strengthening (e.g., from 1:10 to 1:8 grams carbohydrate per unit).

Monitoring Plan

• Check glucose patterns at the same times daily for 3-5 days after each adjustment
• Prioritize overnight/fasting glucose as the most reliable indicator of basal adequacy 5
• Document time-in-range improvements - target should be >70% TIR 2
• Watch for hypoglycemia - if it occurs, reduce the most recent increase by 50%

The combination of increased basal rates and a stronger correction factor should significantly improve your TIR by addressing both baseline hyperglycemia and inadequate correction of glucose excursions 1, 2, 8.