Conversion from Intravenous Insulin to Subcutaneous Insulin After Cardiovascular Surgery: Transition to Target Study

BACKGROUND: No study of transition from intravenous to subcutaneous insulin after cardiac surgery with dose based on percentage of intravenous total daily insulin (TDI) has reported a clearly superior regimen for achieving target blood glucose. We compared three first-dose transition strategies for insulin glargine: two based on TDI alone and one that also took body weight into account. METHODS: Mostly obese, type 1 and type 2 diabetes patients (n = 223) undergoing cardiac surgery were randomized to receive insulin glargine subcutaneously at 60% or 80% of TDI or in a dose based on TDI and body weight. RESULTS: Transition to subcutaneous insulin occurred 27.4 ± 6.6 h after surgery. Over the study period, mean proportion of blood glucose values within target range (80-140 mg/dL) were 0.34 ± 0.24, 0.35 ± 0.24, and 0.36 ± 0.22 in the 60% TDI, 80% TDI, and weight-based groups, respectively. This difference was not significant. Significantly more insulin corrections were needed in the 60% TDI group than in the weight-based group. There was only one incidence of hypoglycemia (blood glucose < 40 mg/dL). CONCLUSIONS: No subcutaneous insulin regimen implemented approximately 1 day after cardiac surgery showed significantly better control of blood glucose over the 3-day study period. Further studies are needed to determine optimal formulae for effecting an early transition to subcutaneous insulin after cardiac surgery or whether it is preferable and/or necessary to continue intravenous insulin therapy for an additional period of time.