Glucose Variability is an Independent Predictor of Mortality in Hospitalized Patients Treated with Total Parenteral Nutrition

Abstract

Hyperglycemia is associated with increased mortality in critically ill patients treated with total parenteral nutrition (TPN). The role of glucose variability (GV) in predicting outcomes in these patients is not known. This retrospective study included medical and surgical patients receiving TPN in a community teaching hospital. GV was calculated by standard deviation (SD) of blood glucose (BG) values and by mean BG daily (Δ) change (daily max - daily minimum). A total of 276 medical and surgical patients (mean age: 51 ± 18 years), 19% with a history of diabetes mellitus (DM), and 74% with intensive care unit (ICU) admission were treated with TPN. During TPN, the mean daily BG was 142.9 ± 33 mg/dL; frequencies of hypoglycemia < 70 and < 40 mg/dL were 41% and 3%, respectively; and hospital mortality was 27.2%. The mean GV by SD was 38 ± 21 mg/dL and by mean (D) change 58 ± 34 mg/dL. GV was significantly higher in deceased patients (SD: 48 ± 25 vs. 34 ± 18 mg/dL and Δ change: 75 ± 39 vs. 51 ± 29 mg/dL, both P < .01) than surviving patients. Multivariate analysis adjusted for age, DM status, gender, APACHE (Acute Physiology and Chronic Health Evaluation) score, mean daily glucose, and hypoglycemia revealed that GV was an independent predictor of hospital mortality (P < .05). The association between GV and mortality was limited to patients without a history of DM and was not present in patients with DM. High GV is associated with increased hospital mortality independent of the presence and severity of hyperglycemia or hypoglycemia during TPN therapy. Prospective randomized trials are needed to determine if reduction in GV with intensive glycemic control improves clinical outcomes in patients treated with TPN.