Sitagliptin for the Prevention and Treatment of Stress Hyperglycemia in Non-Diabetic Patients Undergoing Cardiac Surgery

Subjects will take one pill daily until the day prior to them being discharged from the hospital. Sitagliptin will be dispensed orally at 100 mg/day and at a lower dose 50 mg for patients with glomerular filtration rate (GFR) \< 30-50. If the calculated GFR drops to 30 mL/min/1.73m2 or below, patients will receive study medication 25mg daily

One pill daily until discharge

Continuous intravenous insulin given to ICU patients with a BG \> 180 mg/DL for two consecutive readings and will be started on Regular Human Insulin adjusted to achieve and maintain a BG target between 110 - 180 mg/dL following standard hospital protocol. Intravenous insulin infusion will be continued until the patient is able to eat and/or transferred to non-ICU service. In previous studies, average length of insulin infusion in patients with stress hyperglycemia was 16.9±19 hours and the amount of IV insulin requirement was 18.6±24.3 U/day.

When regular insulin is discontinued, if needed, insulin glargine will be given once daily. Patients who required continuous insulin infusion at an average rate \>2U/h will be transitioned to basal (to be given approx. 4 hours prior to discontinuing the insulin drip) starting at a dose 0.2 U/Kg/d. Subjects with a BG at 140-200 mg/dL will start glargine at 0.2 U/kg weight per day. And subjects with BG between 201-400 mg/dL will start glargine at 0.2 U/Kg/day The basal insulin dose will be adjusted as follow: * If fasting and pre-dinner BG is between 100 - 180 mg/dL in the absence of hypoglycemia the previous day: no change * If fasting and pre-dinner BG is between 180 - 240 mg/dL in the absence of hypoglycemia: increase glargine by 10% every day * If fasting and pre-dinner BG is \> 241 mg/dL in the absence of hypoglycemia the previous day: increase glargine dose by 20% every day * If fasting and pre-dinner BG is \< 100 mg/dL in the absence of hypoglycemia: stop glargine

Insulin lispro will be administered before meals in addition to scheduled insulin dose following the supplemental insulin scale protocol. At bedtime, half of supplemental sliding scale insulin starting at BG \>240 mg/dL will be given. For the subjects receiving supplemental insulin lispro with BG levels greater than 180 mg/dL, then supplemental insulin scale is as follows: * BG between 181-220 mg/dL; 2-4 units of insulin lispro * BG between 221-260 mg/dL; 3-5 units of insulin lispro * BG between 261-300 mg/dL; 4-6 units of insulin lispro * BG between 301-350 mg/dL; 5-7 units of insulin lispro * BG between 351-400 mg/dL; 6-8 units of insulin lispro * BG \> 400 mg/dL; 7-9 units of insulin lispro

Insulin aspart will be administered before meals in addition to scheduled insulin dose following the supplemental insulin scale protocol. At bedtime, half of supplemental sliding scale insulin starting at BG \>240 mg/dL will be given. For the subjects receiving supplemental insulin aspart with BG levels greater than 180 mg/dL, then supplemental insulin scale is as follows: * BG between 181-220 mg/dL; 2-4 units of insulin aspart * BG between 221-260 mg/dL; 3-5 units of insulin aspart * BG between 261-300 mg/dL; 4-6 units of insulin aspart * BG between 301-350 mg/dL; 5-7 units of insulin aspart * BG between 351-400 mg/dL; 6-8 units of insulin aspart * BG \> 400 mg/dL; 7-9 units of insulin aspart