Insulin resistance, secretion and breakdown are increased 9 months following severe burn injury

Abstract

Insulin resistance in the acute burn period has been well described, however, it is unknown if alterations in glucose metabolism persist beyond discharge from the acute injury. To measure the duration of insulin resistance following recovery from the acute burn injury, we performed a prospective cross-sectional study with a standard 2-h oral glucose tolerance test in 46 severely burned children at 6, 9 or 12 months following initial injury. Glucose uptake and insulin secretion were assessed following the glucose load. Results were compared to those previously published in healthy children. At 6 months after burn, the 2-h glucose concentration was significantly (P<0.001) greater than controls, and the area under the curve (AUC) of glucose was significantly higher compared to 12 months and to healthy children (P=0.027 and P<0.001, respectively). The 9-month AUC glucose was higher than controls (P<0.01). The 6-month 2-h insulin was significantly higher than controls, as was the AUC of insulin in all time points post-burn. The AUC of C-peptide was significantly greater at 6 months after injury compared to 9 and 12 months (P<0.01 for both). Increased 2h and AUC glucose and insulin indicate that glucose metabolism is still affected at 6 and 9 months after injury, and coincides with previously documented defects in bone and muscle metabolism at these time points. Insulin breakdown is also still increased in this population. Further study of this population is warranted to determine if specific treatment is needed.

Figure 1

AUC of glucose and Insulin A) AUC of glucose in mg/dL from the OGTT in the three burn groups and the healthy burn group is shown. 6 months was significantly different than healthy and 12 month (P<0.001 and P<0.01)). 9 month was significantly different from healthy (P<0.01). B) AUC of insulin in μU/L from the OGTT in the three burn groups and the healthy group is shown. There were no differences between the patient groups, although all were significantly higher than the healthy group.

Figure 2

C-peptide and insulin/C-peptide measurements during OGTT’s A) The C-peptide concentrations in pmol/L from the OGTT is shown from the three burn groups. The AUC of the 6 month was significantly different than the other time points (P<0.001 vs. 12 month and P<0.01 vs. 9 month). B) Ratio of Insulin/C-peptide (pmol/L for both) is shown for the three post-burn time points.

Figure 2

C-peptide and insulin/C-peptide measurements during OGTT’s A) The C-peptide concentrations in pmol/L from the OGTT is shown from the three burn groups. The AUC of the 6 month was significantly different than the other time points (P<0.001 vs. 12 month and P<0.01 vs. 9 month). B) Ratio of Insulin/C-peptide (pmol/L for both) is shown for the three post-burn time points.