Mortality, Resource Utilization, and Inpatient Costs Vary Among Pediatric Heart Transplant Indications: A Merged Data Set Analysis From the United Network for Organ Sharing and Pediatric Health Information Systems Databases

Abstract

Merging United Network for Organ Sharing (UNOS) and Pediatric Health Information Systems databases has enabled a more granular analysis of pediatric heart transplant outcomes and resource utilization. We evaluated whether transplant indication at time of transplantation was associated with mortality, resource utilization, and inpatient costs during the first year after transplantation. We analyzed transplant outcomes and resource utilization from 2004 to 2015. Patients were categorized as congenital (CHD), myocarditis, or cardiomyopathy based on UNOS-defined primary indication. CHD complexity subgroup analyses (single-ventricle, complex, and simple biventricular CHD) were also performed. Of 2251 transplants (49% CHD, 5% myocarditis, 46% cardiomyopathy), CHD recipients were younger (2 [IQR 0-10], 6 [IQR 0-12], and 7 [IQR 1-14] years, respectively; P < .001) and less likely to have a ventricular assist device (VAD) at transplantation (3%, 27%, and 13%, respectively; P < .001). Patients with single-ventricle CHD had the longest time on the waitlist and were least likely to receive a VAD before transplantation. After adjusting for patient-level factors, transplant recipients with single-ventricle CHD had the greatest mortality during transplantation admission and within 1 year (odds ratio [OR] 11.8 [95% confidence interval (CI) 5.9-23.6] and OR 6.0 [95% CI 3.6-10.2], respectively, vs cardiomyopathy). Mortality was similar between patients with myocarditis and cardiomyopathy. Post-transplantation length of stay (LOS) was longer in transplant recipients with CHD than myocarditis or cardiomyopathy (25 [interquartile range [IQR] 15-45] vs 21 [IQR 12-35] vs 16 [IQR 12-25] days; P < .001), related in part to longer duration of intensive care unit-level care (ICU LOS 8 [IQR 4-20] vs 6 [IQR 4-13] vs 5 [IQR 3-8] days; P < .001). Similarly, patients with CHD had higher median post-transplantation costs than myocarditis or cardiomyopathy ($415K [IQR $201K-503K] vs $354K [IQR $179K-390K] vs $284K [IQR $145K-319K]; P < .001) that persisted after adjusting for patient-level factors (adjusted cost ratio 1.4 [95% CI 1.4-1.5], CHD vs cardiomyopathy) and was primarily driven by longer LOS. More than 50% were readmitted during the first year after transplantation, although readmission rates were similar across transplant indications (P = .42). Children with CHD, particularly single-ventricle patients, require substantially greater hospital resource utilization and have significantly worse outcomes during the first year after heart transplantation compared with other indications. Further work is aimed at identifying modifiable pre-transplantation risk factors, such as pre-transplantation conditioning with VAD support and cardiac rehabilitation, to improve post-transplantation outcomes and reduce resource utilization in this complex population.