Competing risks for death and cardiac transplantation in children with dilated cardiomyopathy: Results from the pediatric cardiomyopathy registry

Background: Pediatric dilated cardiomyopathy (DCM) is the leading indication for heart transplantation after 1 year of age. Risk factors by etiology at clinical presentation have not been determined separately for death and transplantation in population-based studies. Competing risks analysis may inform patient prioritization for transplantation listing. Methods and results: The Pediatric Cardiomyopathy Registry enrolled 1731 children diagnosed with DCM from 1990 to 2007. Etiologic, demographic, and echocardiographic data collected at diagnosis were analyzed with competing risks methods stratified by DCM etiology to identify predictors of death and transplantation. For idiopathic DCM (n=1192), diagnosis after 6 years of age, congestive heart failure, and lower left ventricular (LV) fractional shortening z score were independently associated with both death and transplantation equally. In contrast, increased LV end-diastolic dimension z score was associated only with transplantation, whereas lower height-for-age z score was associated only with death. For neuromuscular disease (n=139), lower LV fractional shortening was associated equally with both end points, but increased LV end-diastolic dimension was associated only with transplantation. The risks of death and transplantation were increased equally for older age at diagnosis, congestive heart failure, and increased LV end-diastolic dimension among those with myocarditis (n=272) and for congestive heart failure and decreased LV fractional shortening among those with familial DCM (n=79). Conclusions: Risk factors for death and transplantation in children varied by DCM etiology. For idiopathic DCM, increased LV end-diastolic dimension was associated with increased transplantation risk but not mortality. Conversely, short stature was significantly related to death but not transplantation. These findings may present an opportunity to improve the transplantation selection algorithm.