A study comparing the hypoglycemic effects of evening and morning injections in patients with non-insulin dependent diabetes (NIDDM) was conducted by the University of Helsinki, Finland (Diabetes Care, August 1994). Researchers determined that the hypoglycemic effects of the two treatments were similar. For patients using a combination of Regular and NPH therapy, insulin can be administered equally well during the night and during the day. The researchers were trying to determine when glucose production is most abnormal. They had hypothesized that nocturnal insulin injections might be more effective, because glucose production in the body is maximal during the night.
Researchers compared the effects of 12-hour nighttime or daytime infusions to collect a 24-hour glucose profile for 20 patients with type 2 diabetes. Patients were studied twice a week and on both occasions blood glucose, insulin, C-peptide, and free fatty acid (FFA) concentrations were determined for the 24-hour period. On one occasion, patients would receive a 12-hour intravenous injection during the day and on the next an identical dose during the night. While better suppression of FFA was noted using nighttime insulin injections, this effect did not significantly lower blood glucose levels.
Scientists cautioned however, that these studies do not necessarily reflect the long term effects of these therapies.