Glucose variability is associated with high mortality after severe burn

Background: Hyperglycemia is associated with increased mortality in the severely injured; intensive insulin protocols reduce mortality, improve wound healing, and decrease susceptibility to infection. High glucose variability creates challenges to glycemic control and may be a marker of poor outcome. We wondered whether glycemic variability alone might identify patients at higher risk of death. Methods: Burn patients admitted in 2005 with >20% total body surface area burned, ≥100 glucose measurements, and one hypo- and hyperglycemic event were included in the analysis; all were treated with intensive insulin (glycemic target: 80-110 mg/dL). Glycemic variability was the sum of percent excursions (defined as values <80 mg/dL or >110 mg/dL); variability above the mean was considered high. Results: Individual average variability in the 49 subjects was 50% ± 8% (range, 30-65%); the average number of glucose measurements per patient was 840 (range, 103-5314). Percent excursions in those with high (n = 26) compared with low (n = 23) variability scores was 56% ± 6% and 43% ± 5% (p < 0.001), respectively. No difference was found between groups in injury severity score, age, total body surface area burned, full thickness burns, gender, or inhalation injury. Both groups were similar for days of ventilator support, intensive care unit stay, and hospital stay. Mortality in the highly variable group was twice that of the less variable group (50% vs. 22%, p = 0.041). ConclusionS: High glucose variability (>50% of values outside 80-110 mg/dL) is associated with increased mortality in the severely burned. Individuals with frequent excursions outside the glucose target range of 80 mg/dL to 110 mg/dL are at greater risk of death.