Hyperglycemia prior to, and shortly after, initiation of total parenteral nutrition was strongly associated with poor clinical outcomes in critically ill hospitalized patients, whether or not they had a history of diabetes, Emory University researchers determined in a retrospective study.
Patients had an almost threefold risk of dying if their maximum blood glucose before or within 24 hours of beginning total parenteral nutrition (TPN) was more than 180 mg/dL, compared with patients whose maximum blood glucose was less than 120 mg/dL in the same time period.
Many other factors were taken into account for the statistical analysis, including age, sex, and diabetes status, Dr. Guillermo E. Umpierrez, professor of medicine at Emory University, Atlanta, said at the Southern regional meeting of the American Federation for Medical Research.
He described hyperglycemia as a common complication of TPN, but said its prevalence and impact on clinical outcomes have been uncertain.
Dr. Umpierrez and his associates reviewed the records of 276 medical/surgery patients who required TPN a mean 11 days after admission. The majority came from surgical or medical intensive care units or the burn unit, but nearly 25% came from non-ICU floors. Twenty-three percent had a history of diabetes.
Patients received TPN for a mean duration of 15 days. In-hospital mortality was 27% (75 patients).
Patients who died had a higher maximum blood glucose before initiation of TPN (mean 147 mg/dL) than those who survived (mean 131 mg/dL), as well as a higher maximum blood glucose reading within 24 hours of TPN initiation (mean 202 mg/dL, compared with mean 160 mg/dL). The differences in blood glucose were highly statistically significant at both time points.
A multivariate analysis found that not only mortality but the risk of pneumonia and acute renal failure were independently related to maximum blood glucose levels of greater than 180 mg/dL versus mean blood glucose levels of less than 120 mg/dL.
In a later interview, Dr. Umpierrez said that pre-TPN blood glucose levels could alert medical teams to the possibility of TPN-related hyperglycemia, allowing for anticipatory management.
“Hospitalists should pay attention to blood glucose levels, not only in those receiving TPN but in patients with hyperglycemia before TPN,” Dr. Umpierrez said. “Frequent blood glucose monitoring is needed to prevent and/or correct hyperglycemia.”
At his institution, the findings prompted a change in protocol to initiate insulin infusion as TPN is begun or to start insulin infusion in patients on TPN whose blood glucose is “persistently elevated,” which he defined as a level over 140 mg/dL.
Dr. Umpierrez' research is supported by grants from the American Diabetes Association and the National Institutes of Health.