Beta-score: an assessment of beta-cell function after islet transplantation.
OBJECTIVE
Success after islet transplantation can be defined in 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.


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, the HbA(1c) was >6.9%, C-peptide secretion was absent on stimulation, or daily insulin use was in excess of 0.24 units/kg. One point was given for intermediate values. The score ranged from 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 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.
Ryan
Edmond A
EA
Heritage Medical Research Centre, Edmonton, Alberta, Canada T6G 2S2. edmond.ryan@ualberta.ca
Paty
Breay W
BW
Senior
Peter A
PA
Lakey
Jonathan R T
JR
Bigam
David
D
Shapiro
A M James
AM
D001786:Blood Glucose; D002096:C-Peptide / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis* / Q000188:drug therapy / Q000601:surgery*; D006442:Glycated Hemoglobin / Q000378:metabolism; D006085:Graft Survival / Q000502:physiology*; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D007515:Islets of Langerhans / Q000502:physiology*; D016381:Islets of Langerhans Transplantation; D019518:Postprandial Period; D012720:Severity of Illness Index
D001786:Blood Glucose; D002096:C-Peptide; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents