Table 4.
Case Examples to Put Our Approach Into Practice for Adults
| Examples Assume ICR and CF Values Have Been Accurately Determined by the Patient’s Health Care Team and That the Patient is Administering Rapid-Acting Insulin for Boluses and Corrections. Examples Assume the Patients Have Insulin-Requiring Diabetes and Are Using Dexcom G5 rtCGM. | ||||||||
|---|---|---|---|---|---|---|---|---|
| A | A 35-year-old, MDI-treated man sits down to eat a meal with 35 g carbohydrate. A SINGLE UP arrow is present. A calculated insulin dose is determined using meal and correction parameters. Due to the single UP arrow and no plan to exercise, an adjustment of +2.5 U is suggested. This increases the total insulin dose to 8.0 U. | |||||||
| Sensor Glucose | Trend Arrow | Target Glucose | Carb | Parameters | Calculated Insulin Dose | Trend Arrow Adjustment | Total Insulin Dose | |
| 180 mg/dL | ↑ | 120 mg/dL | 35 g | CF–30 | 2.0 U + 3.5 U = 5.5 U | +2.5 U | 8.0 U | |
| ICR–1:10 | ||||||||
| B | A 52-year-old woman on insulin pump therapy is eating 30 g of carbohydrate for lunch and sees a SINGLE DOWN arrow. The calculated insulin dose is determined. A negative adjustment of −1.5 U is suggested to account for the falling blood glucose and to prevent hypoglycemia. This decreases the total insulin dose to 2.5 U. (Note: An MDI-treated individual may round the total insulin dose to 2.0 U.) | |||||||
| Sensor Glucose | Trend Arrow | Target Glucose | Carb | Parameters | Calculated Insulin Dose | Trend Arrow Adjustment | Total Insulin Dose | |
| 220 mg/dL | ↓ | 120 mg/dL | 30 g | CF–50 | 2.0 U + 2.0 U = 4.0 U | −1.5 U | 2.5 U | |
| ICR–1:15 | ||||||||
| C | A 75-year-old man on MDI therapy is about to eat a meal with 50 g of carbohydrate. His sensor glucose is elevated and a SINGLE DOWN arrow is present. The calculated insulin dose is determined. A negative adjustment of −1.5 U is suggested to account for the falling blood glucose and prevent hypoglycemia. However, due to the frailty of the patient, the adjustment is further reduced by at least 50% (i.e., further reduced by at least 0.75 U in this case). Out of an abundance of caution and convenience of rounding to whole units, the man decides to reduce by 1.0 U for a total negative adjustment of −2.5 U. This decreases the total insulin dose to 2.0 U. | |||||||
| Sensor Glucose | Trend Arrow | Target Glucose | Carb | Parameters | Calculated Insulin Dose | Trend Arrow Adjustment | Total Insulin Dose | |
| 240 mg/dL | ↓ | 120 mg/dL | 50 g | CF–60 | 2.0 U + 2.5 U = 4.5 U | −2.5 U | 2.0 U | |
| ICR–1:20 | ||||||||
| D | A 28-year-old man on insulin pump therapy is noticing a mildly elevated sensor glucose and an ANGLE DOWN arrow 90 minutes after eating a meal with 45 g of carbohydrate. He is considering taking a little extra insulin. However, he follows the suggestions for postmeal monitoring and hypoglycemia prevention and determines that neither a correction nor an adjustment is needed at this time. He will recheck his sensor glucose in 30 minutes. | |||||||
| Sensor Glucose | Trend Arrow | Target Glucose | Carb | Parameters | Calculated Insulin Dose | Trend Arrow Adjustment | Total Insulin Dose | |
| 170 mg/dL | ↘ | 120 mg/dL | 0 g | CF–50 | NA | NA | NA | |
| ICR–1:10 | ||||||||
| E | A 23-year-old woman on MDI therapy is experiencing hyperglycemia 2.5 hours after eating a meal with 45 g of carbohydrate. At the time of eating, she took the appropriate amount of insulin and did not need a correction. Now she is seeing DOUBLE UP arrows. Because she is within 4 hours of eating, she will follow the suggestions for postmeal monitoring and hyperglycemia prevention and will not use the adjustment table. Also, she is an MDI-treated patient who is not using a bolus calculator that accounts for insulin-on-board. Therefore, she reduces the calculated correction insulin dose of 2.0 U by 50% to prevent overcorrection. This reduces the total insulin dose to 1.0 U. She will recheck in 1 hour. | |||||||
| Sensor Glucose | Trend Arrow | Target Glucose | Carb | Parameters | Calculated Insulin Dose | Trend Arrow Adjustment | Total Insulin Dose | |
| 240 mg/dL | ↑↑ | 120 mg/dL | 0 g | CF–60 | 2.0 U × 50% = 1.0 U | NA | 1.0 U | |
| ICR–1:10 | ||||||||
| F | A 49-year-old man on insulin pump therapy is working late into a stressful afternoon. Lunch was nearly 5 hours ago. He notices his sensor glucose is elevated with an ANGLE UP arrow. He calculates his insulin dose for correction using predetermined values and then uses the adjustment table to account for the rising blood glucose. He uses the adjustment table because he is beyond 4 hours from his last meal and there shouldn’t be any active insulin-on-board from his mealtime bolus. He adds the adjustment of 1.5 U, which increases his total insulin dose to 3.8 U. | |||||||
| Sensor Glucose | Trend Arrow | Target Glucose | Carb | Parameters | Calculated Insulin Dose | Trend Arrow Adjustment | Total Insulin Dose | |
| 180 mg/dL | ↗ | 100 mg/dL | 0 g | CF–35 | 2.3 U | +1.5 U | 3.8 U | |
| ICR–1:8 | ||||||||
| G | A 35-year-old woman has been struggling with a headache all morning. She takes 1 g of acetaminophen. After 1 hour, she notices a high sensor glucose value and DOUBLE UP arrows. However, she recalls that the Dexcom G5 can yield falsely high readings when acetaminophen is used. She checks her blood glucose by fingerstick and does not use the trend arrow data or adjustment table. The fingerstick reading shows she is actually at 115 mg/dL. No correction is needed. She will continue to use fingerstick monitoring until 6 hours has passed since ingesting the acetaminophen. | |||||||
| Sensor Glucose | Trend Arrow | Target Glucose | Carb | Parameters | Calculated Insulin Dose | Trend Arrow Adjustment | Total Insulin Dose | |
| 243 mg/dL | ↑↑ | 120 mg/dL | 0 g | CF–70 | 0.0 U | NA | 0.0 U | |
| ICR–1:20 | ||||||||
| H | A 38-year-old woman on MDI therapy has had to walk much more than usual during her midday work. She managed to stay near her target glucose; however, as she prepares for her lunch, she sees DOUBLE DOWN arrows. She calculates the insulin dose a slight correction and her meal with 45 g carbohydrate. Then she uses the adjustment table, which suggests a negative adjustment of −3.5 U. After rounding, this is a net total insulin dose of 0.0 U. She will eat without taking an insulin dose and carefully monitor the rest of the afternoon. (Note: If she was consuming less carbohydrate or was below target glucose, a negative total insulin dose may result, in which case, 15 g of fast-acting carbohydrate and close monitoring until trend arrows stabilize may be more appropriate than consuming her typical lunch.) | |||||||
| Sensor Glucose | Trend Arrow | Target Glucose | Carb | Parameters | Calculated Insulin Dose | Trend Arrow Adjustment | Total Insulin Dose | |
| 160 mg/dL | ↓↓ | 130 mg/dL | 45 g | CF–45 | 0.7 U + 3.0 U = 3.7 U | −3.5 U | 0.0 U | |
| ICR–1:15 | ||||||||
Calculated Insulin Dose includes insulin needed to cover carbohydrate intake and correction to reach target glucose. The calculations use the predetermined ICR and CF values and assume these values have been accurately determined by the patient’s health care team and that the patient is using rapid-acting insulin for carbohydrate intake and correction.
Abbreviations: CF, correction factor in mg/dL indicates glucose lowering per unit of rapid-acting insulin; U, units of rapid-acting insulin. Conversion: mg/dL × 0.0555 = mmol/L.