A total daily insulin dose of about 0.2 U/kg was optimal to cover the fast day, "although there is considerable variability between patients."…
The actual daily dose patients used during successful 25-hour fasts varied between about 0.05 and 0.55 U/kg, report David Gillis (Hadassah-Hebrew University Medical Center, Jerusalem, Israel) and co-workers.
The team studied 57 children and young adults with type 1 diabetes, aged between 12 and 31 years, who undertook 88 fasts lasting about 25 hours each during two Jewish religious fasts. In all, 78.4% of these fasts were successful, whereas patients were unable to complete 21.6% of fasts. The most common reason for not completing the fast was mild hypoglycemia, although no patient had a severe episode.
Patients who did and did not complete a fast used a similar usual daily basal insulin dose, at 0.38 and 0.44 U/kg, respectively.
However, the average doses used during the fast day were significantly different, at 0.19 U/kg during successful fasts versus 0.34 U/kg during unsuccessful fasts. This equated to a 48.5% reduction from usual insulin dose among patients who completed their fast versus a 22.6% reduction among those who did not.
Patients took correction doses during 43.5% of successful fasts, and they took an average correction dose of 0.03 U/kg per day.
The association between a larger insulin dose reduction and a successful fast was present in the subgroup of 30 continuous subcutaneous insulin infusion users, but the difference was not significant among the 28 patients who used multiple daily insulin injections.
Based on these data, the researchers suggest that an insulin dose of 0.2 U/kg per day will facilitate a successful fast, although they note that this "is a general recommendation which clearly cannot apply across the board."
For example, they found that a slightly higher daily dose was needed among children younger than 16 years, at 0.230 U/kg compared with 0.186 U/kg among older patients. The dose would also need to be reduced in patients whose usual daily dose was low, and probably raised in obese patients, they say.
"These reservations do not detract from the use of 0.2 U/kg/day as a good starting dose that may require adjustments," the team concludes. "A similar recommendation can be made for fasting prior to medical procedures."
- An insulin dose of 0.2 U/kg per day can facilitate a successful fast, but needs to be increased for obese children
- Patients took correction doses during 43.5% of successful fasts, and they took an average correction dose of 0.03 U/kg per day
- There was considerable variability between patients
Pediatr Diabetes 2014; Advance online publication 31 July 2014