The proportion of single and sequential donor islet allograft recipients with full (insulin independence and HbA1c <7%) and partial (insulin dependence, basal or arginine-stimulated C-peptide levels of greater or equal to 0.5 ng/mL and HbA1c <7%) islet graft function at one year after the final islet transplant will be assessed. The impact of islet transplantation on quality of life will also be assessed.