Young adult heart transplantation (HTx) recipients experience high mortality risk attributed to increased nonadherence to immunosuppressive medication in this age window. This study sought to test whether a high-risk age window in HTx recipients persisted in the absence of reported nonadherence.Methods
Heart transplantation recipients aged 2 to 40 years, transplanted between October 1999 and January 2007, were identified in the United Network for Organ Sharing database. Multivariable survival analysis was used to estimate influences of age at transplantation and attained posttransplant age on mortality hazard among patients stratified by center report of nonadherence to immunosuppression that compromised recovery.Results
Three thousand eighty-one HTx recipients were included, with univariate analysis demonstrating peak hazards of mortality and reported nonadherence among 567 patients transplanted between ages 17 and 24 years. Multivariable analysis adjusting for reported nonadherence demonstrated lower mortality among patients transplanted at younger (hazards ratio, 0.813; 95% confidence interval, 0.663-0.997; P = 0.047) or older (hazards ratio, 0.835; 95% confidence interval, 0.701-0.994; P = 0.042) ages. Peak mortality hazard at ages 17 to 24 years was confirmed in the subgroup of patients with no nonadherence reported during follow-up. This result was replicated using attained age after HTx as the time metric, with younger and older ages predicting improved survival in the absence of reported nonadherence.Conclusions
Late adolescence and young adulthood coincide with greater mortality hazard and greater chances of nonadherence to immunosuppressive medication after HTx, but the elevation of mortality hazard in this age range persists in the absence of reported nonadherence. Other causes of the high-risk age window for post-HTx mortality should be demonstrated to identify opportunities for intervention.