Glycemic control in patients with diabetes mellitus receiving total parenteral nutrition (TPN) can be challenging due to multiple factors. These patients often have a high burden of illness and receive medications that raise blood glucose (BG) levels. Moreover, TPN delivers a large amount of glucose directly into the systemic circulation without the benefit of incretin effect. Therefore, relatively large amounts of insulin are expected to be required for glycemic control. However, there are no studies to guide insulin dosing in patients with diabetes being started on TPN. We conducted a retrospective study including all patients with diabetes admitted to our hospital over a 1-year period who received TPN for ≥ 3 days. The goal of this study was to estimate a safe starting dose of insulin for TPN. Patients receiving enteral nutrition along with TPN were excluded. Insulin doses and blood glucose levels on the last day of TPN were used for data analysis. We found 25 patients who fulfilled our inclusion/exclusion criteria. All patients had type 2 diabetes and were receiving antidiabetic drugs before hospitalization. Mean age was 68 ± 7 years, 56% were men, 80% were White, 44% had microvascular and 44% had macrovascular complications. Mean BMI was 26.7 ± 6.7 kg/m2, systolic BP 131 ± 27 mmHg, diastolic BP 65 ± 15 mmHg, HbA1c 7.7 ± 2.3% and serum creatinine 2.7 ± 3.3 mg/dl. The mean daily BG on TPN was 212 ± 47 mg/dl. Out of 171 BG values available on the last day of TPN, 116 (68%) were >180 mg/dl, 4 (2%) were <70 mg/dl and 0 were <40 mg/dl. Only two patients suffered mild hypoglycemic episodes while all others remained hyperglycemic. Average total daily insulin dose was 17 ± 20 units before starting TPN and 53 ± 54 units on the last day of TPN. Patients received an average of 0.7 Units/kg total daily dose of insulin on the last day of TPN. With this dose, they had minimal risk of hypoglycemia but the glucose levels were often high. Our study shows that the majority of patients with diabetes need more than 0.7 units/kg insulin when receiving TPN.
R. Garg: None. A. Arunachalam: None. L.E. Bermudez: None. M. Ramirez: None.