β-Score -: An assessment of β-cell function after islet transplantation

OBJECTIVE - Success after islet transplantation can be defined ill terms of insulin independence, C-peptide secretion, or glycemic control. These measures are interdependent and all need to be considered in evaluating beta-cell function after islet transplantation. For the current study a composite beta-score was developed that provides an integrated measure of beta-cell function success after islet transplantation. RESEARCH DESIGN AND METHODS - The proposed scoring system gave 2 points each for normal fasting glucose, HbA(1c), stimulated C-peptide, and absence of insulin or oral hypoglycemic agent use. No points were awarded if the fasting glucose was in the diabetic range, P the HbA(1c) was >6.9%, C-peptide secretion was absent oil stimulation, or daily insulin use was in excess of 0.24 units/kg. One point was given for intermediate values. The score ranged front 0 to 8 and was correlated With the glucose value 90 min after a standard mixed meal challenge (n = 218) in 57 subjects before and after islet transplantation. The score was also used to follow subjects for up to 5 years after islet transplantation. RESULTS - The beta-score correlated well with the plasma glucose level 90 min after a mixed meal challenge (r = -0.849, P < 0.001). On follow-up, the beta-score rose after the first transplant n and was maintained up to 5 years, demonstrating continuing function of the transplanted beta-cells. CONCLUSIONS - The beta-score provides a simple clinical scoring system that encompasses glycemic control, diabetes therapy, and endogenous insulin secretion that correlates well with physiological measures of beta-cell function. On this basis, it is suitable as an overall measure of beta-cell transplant function. The beta-score gives an integrated measure of beta-cell function as a continuum that may be more useful than simply assessing the presence or absence of insulin independence. Diabetes Care 28:343-347, 2005.