Metabolic effect of hemipancreatectomy in donors. Preoperative prediction of postoperative oral glucose tolerance.

Between November 1977 and January 1987, 55 transplantations of pancreas segments from living donors related to their recipients were performed at the University of Minnesota. A preliminary analysis of metabolic test results in donors tested 1 yr after hemipancreatectomy showed an increase in mean glucose and a decrease in mean insulin values during oral glucose tolerance tests (OGTTs) in 18 donors, a 14% increase in the mean of the mean glucose levels during 24-h metabolic profiles in 12 donors, and a decrease of 45% in the mean 24-h urinary C-peptide excretion in 21 donors. Including the studies performed postdonation, 11 of 31 (35%) donors developed an abnormal OGTT result. In a retrospective analysis, preoperative results of intravenous glucose tolerance tests (IVGTTs) and cortisone-stimulated OGTTs were found to be statistically significant predictors of an abnormal OGTT after hemipancreatectomy. The mean of the 5- to 50-min IVGTT insulin values was the best predictive test. With the cutoff value set at 62 microU/ml, this test result had a sensitivity of 100%, a specificity of 83%, and a positive predictive value of 75% for identifying donors who developed an abnormal OGTT. The sum of the 5- and 10-min IVGTT insulin (cutoff 140 microU/ml) had a sensitivity of 100%, a specificity of 67%, and a predictive value of only 60%, whereas the delta-insulin had values of 86, 71, and 60%, respectively. Both the IVGTT mean insulin and the sum of the 5-min and 10-min insulin test results were 100% predictive of an abnormal test (0% risk), but the IVGTT mean insulin excluded the lowest proportion of otherwise suitable donors (a low "false-alarm" rate). The IVGTT mean insulin can be used to identify or exclude potential donors who would develop an abnormal OGTT result should hemipancreatectomy be performed.