Objective Our objective was to characterise the divergence of effort from outcome in congenital heart disease (CHD) care by measuring mortality-related resource utilisation fraction (MRRUF) for various CHD lesions across institutions of differing volumes.

Methods Study design was observational analysis of an administrative database, the Pediatric Health Information System (PHIS). The setting was inpatient; 2004–2013. Patients were ≤21 years old with atrial septal defect (ASD), ventricular septal defect (VSD), tetralogy of Fallot (TOF), hypoplastic left heart syndrome (HLHS) or other single ventricle (SV). There were no interventions but diagnosis, institution (and volume), age, length of hospitalisation, billed charges and deaths were recorded. The main outcome measure was MRRUF, the ratio of investments during hospitalisations ending in fatality to investments during all hospitalisations.

Results There were 50 939 admissions, 1711 deaths, 703 383 inpatient days, and $10 182 000 000 billed charges. MRRUF varied widely by diagnosis: highest in HLHS (21%), but present in ASD (2%) and VSD (4%). Highest among the very young, MRRUF also increased in HLHS and SV during adolescence. MRRUF increased with hospitalisation duration. MRRUF had no relation to institutional volume, and was static over the decade studied.

Conclusions Even in the modern era we invest heavily in inpatient CHD care that does not produce the desired outcome. Although its magnitude varies by lesion and age, MRRUF is not limited to complex disease in the very young. MRRUF is not decreasing, and is not isolated to high or low volume institutions.