Validation of Igls Criteria for Islet Transplant Functional Status Using Person-Reported Outcome Measures in a Cross-Sectional Study

Abstract

Associations between islet graft function and well-being in islet transplant recipients requiring exogenous insulin remain unclear. This cross-sectional analysis compared person-reported outcome measures in 15 adults with type 1 diabetes whose islet transplants were classified according to Igls criteria as “Good” (n = 5), “Marginal” (n = 4) and “Failed” (n = 6) graft function. At a mean of 6.2 years post-first islet transplant, 90% reduction in severe hypoglycaemia was maintained in all groups, with HbA1c (mean ± SD mmol/mol) 49 ± 4 in recipients with “Good” function; 56 ± 5 (“Marginal”); and 69 ± 25 (“Failed”). Self-reported impaired awareness of hypoglycaemia persisted in all groups but those with “Good” function were more likely to experience symptoms during hypoglycaemia. “Marginal” function was associated with greater fear of hypoglycaemia (HFS-II score: “Marginal”: 113 [95, 119]; “Failed”: 63 [42, 93] (p = 0.082); “Good”: 33 [29, 61]) and severe anxiety (GAD7: “Marginal”): 21 [17, 21]; “Failed”: 6 [6, 6] “Good”: 6 [3, 11]; (p = 0.079)), diabetes distress and low mood. Despite clear evidence of ongoing clinical benefit, Igls criteria ‘Marginal’ function is associated with sub-optimal well-being, including greater fear of hypoglycaemia and severe anxiety. This study provides person-reported validation that “Good” and “Marginal” graft function are differentiated by general and diabetes-specific subjective well-being, suggesting those with “Marginal” function may benefit from further intervention, including re-transplantation.