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 The Pediatric Health Information Systems (UNOS-PHIS) Databases.

BACKGROUND: Merging UNOS and PHIS databases have 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 post-transplant.

METHODS: We analyzed transplant outcomes and resource utilization between 2004 and 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.

RESULTS: Of 2251 transplants (49% CHD, 5% myocarditis, 46% cardiomyopathy), CHD recipients were younger (2 [IQR 0-10] vs. 6 [IQR 0-12] vs. 7 [IQR 1-14] years, respectively; p<0.001) and less likely to have ventricular assist device (VAD) at transplant (CHD 3%, myocarditis 27%, cardiomyopathy 13%; p<0.001). Patients with single ventricle CHD had the longest waitlist and were least likely to receive a VAD pre-transplant. After adjusting for patient-level factors, transplant recipients with single ventricle CHD had the greatest mortality during transplant-admission and at 1-year (vs. cardiomyopathy, OR 11.8 [95% CI 5.9-23.6] and OR 6.0 [95% CI 3.6-10.2], respectively). Mortality was similar between patients with myocarditis and cardiomyopathy. Post-transplant length of stay (LOS) was longer in transplant recipients with CHD than myocarditis or cardiomyopathy (25 [IQR 15-45] vs. 21 [IQR 12-35] vs. 16 [IQR 12-25] days; p<0.001), partially related to longer duration of ICU-level care (ICU LOS 8 [IQR 4-20] vs. 6 [IQR 4-13] vs. 5 [IQR 3-8] days; p<0.001). Similarly, patients with CHD had higher median post-transplant costs than myocarditis or cardiomyopathy ($415k [IQR $201-503k] vs. $354k [IQR $179-390k] vs. $284k [IQR $145-319k]; p<0.001) that persisted after adjusting for patient-level factors (CHD vs. cardiomyopathy Adjusted Cost Ratio 1.4 [95% CI 1.4-1.5]) and was primarily driven by longer LOS. Over 50% were readmitted during first year post-transplant, although readmission rates were similar across transplant indications (p=0.42).

CONCLUSION: Children with CHD, particularly single ventricle patients, require substantially greater hospital resource utilization and have significantly worse outcomes during the first year after heart transplant compared to other indications. Further work is aimed at identifying modifiable pre-transplant risk factors, such as pre-transplant conditioning with VAD support and cardiac rehabilitation, to improve post-transplant outcomes and reduce resource utilization in this complex population.