Abstract 16801: Improved Transplant-Free Survival of Children With Dilated Cardiomyopathy: Analysis of Two Decades From the Pediatric Cardiomyopathy Registry

Abstract

Background: Previous studies of pediatric patients with dilated cardiomyopathy (DCM) have suggested improvement in survival has been due to utilization of heart transplantation. We sought to characterize the changing clinical characteristics and outcomes of pediatric patients with DCM phenotype over the past two decades. Methods: Longitudinal data from 1953 children diagnosed with DCM in the NHLBI Pediatric Cardiomyopathy Registry (PCMR) from 1990-2009 were divided into two cohorts based upon year of diagnosis: “Era 1” (1990-1999, n=1199) and “Era 2” (2000-2009, n=754). Clinical information at diagnosis and incidence of transplant and death without transplant were analyzed by DCM etiology and era. Competing risks methodology was used to estimate the cumulative incidence of death or transplant by era. Results: The majority of patients in both groups had idiopathic DCM (71 vs. 71%, p=0.96). Median age (1.6 vs. 1.7 yrs, p=0.45), left ventricular end diastolic Z scores (+4.2 vs. +4.2, p=0.84) and fractional shortening (16 vs. 17%, p=0.28) at diagnosis were similar. Era 2 patients were more likely to be treated with ACE inhibitors (71 vs. 62%, p=0.004), beta-blockers (24 vs. 6%, p<0.001), and diuretics (89 vs. 84%, p=0.002). A total of 291 patients (15%) died without transplantation, with a median time from diagnosis to death of 0.4 years. Cox regression modeling demonstrated Era 1 was associated with a higher rate of death (HR=1.5, 95% CI=1.2-2.0, p=0.002) but not transplant (0.9, 95% CI=0.7-1.1, p=0.25) when controlling for etiology group. Competing risks estimate (Figure) showed that Era 1 was associated with a higher death rate (p<0.001), while heart transplant rate was not significantly different by era (p=0.068). Conclusions: Children with DCM phenotype have improved survival in the more recent era. This appears to be associated with factors other than the availability of transplantation, which was equally prevalent in both eras.