ABSTRACT
Background: A national registry of congenital heart disease (CHD) would facilitate project initiation, decrease costs, increase statistical power, and avoid duplication. Establishing such registries poses numerous challenges, but the current Canadian research ecosystem in CHD is well positioned to meet them. We assessed the feasibility of building a province-wide CHD registry by automatically identifying people with CHD and extracting their native cardiac anatomy from multiple clinical data sources, without the need for manual data entry. Methods: We designed a CHD registry of all fetuses and children with at least 1 echocardiographic report confirming CHD since 2000. We interfaced the registry with several clinical and echocardiography data sources from all paediatric cardiology programmes in Québec. Results: We extracted 885,287 echocardiogram reports and 70,121 clinical records. We identified CHD in 43,452 children and 4682 fetuses. There were 1128 (2.3%) cases with files in multiple institutions, and patients with more complex CHD were 3 times more likely to be seen in more than 1 institution. So far, the registry has been used to build and link CHD cohorts for 7 distinct projects. Conclusions: We demonstrated the feasibility of a baseline CHD registry in Québec without the need for manual data entry, in which other CHD research projects could be nested. This could serve as a blueprint to expand the registry and to develop an integrated approach where data gathered in caring for patients with CHD serve as data layers that incrementally contribute to a national cohort, for which data remain easily accessible and usable.
Contexte: Un registre national des cardiopathies congénitales (CC) pourrait faciliter le lancement de projets de recherche, en diminuer les coûts, en améliorer la puissance statistique tout en évitant les redondances. La mise en place de tels registres pose de nombreux défis, mais l'écosystème de recherche canadien dans le domaine de la CC est bien placé pour y répondre. Nous avons évalué la faisabilité de la mise en place d'un registre des CC à l'échelle provinciale par l'identification automatique des personnes atteintes de CC et l'extraction de leur anatomie cardiaque native à partir de plusieurs sources de données cliniques, sans nécessiter de saisie manuelle de données. Méthodologie: Nous avons conçu un registre des CC incluant tous les fÅtus et les enfants pour qui au moins un rapport d'évaluation électrocardiographique confirmait la présence d'une CC depuis 2000. Le registre a été mis en relation avec plusieurs sources de données cliniques et échocardiographiques provenant de tous les programmes en cardiologie pédiatrique au Québec. Résultats: Nous avons extrait 885 287 rapports d'échocardiographie et 70 121 dossiers cliniques. La présence d'une CC a été établie chez 43 452 enfants et 4 682 fÅtus. Dans 1 128 cas (2,3 %), un dossier existait dans plus d'un établissement. Les patients présentant des CC plus complexes étaient 3 fois plus susceptibles d'être suivis dans plus d'un établissement. Jusqu'à présent, le registre a été utilisé pour établir et mettre en relation des cohortes de patients atteints de CC pour sept projets de recherche distincts. Conclusions: Nous avons démontré la faisabilité de la mise en place d'un registre de référence des CC au Québec sans recours à la saisie manuelle de données, dans lequel peuvent se nicher d'autres projets de recherche sur les CC. Notre démarche pourrait servir de prototype pour une expansion du registre et pour une approche d'intégration des données recueillies dans la prestation de soins aux patients atteints de CC, afin de former des couches de données qui s'ajoutent au fur et à mesure à une cohorte nationale, avec des données faciles à obtenir et à utiliser.
ABSTRACT
BACKGROUND: Patients are usually maintained on at least 2 immunosuppressive drugs (ISDs) after the first year post heart transplant. Anecdotally, some children are switched to single-drug monotherapy (a single ISD) for various reasons and varying durations. Outcomes associated with differences in immunosuppression after heart transplantation are unknown for children. OBJECTIVES: A priori we defined a noninferiority hypothesis for monotherapy compared to ≥2 ISDs. The primary outcome was graft failure, a composite of death and retransplantation. Secondary outcomes included rejection, infection, malignancy, cardiac allograft vasculopathy and dialysis. METHODS: This international, multicenter, retrospective, observational cohort study used data from the Pediatric Heart Transplant Society. We included patients who underwent first-time heart transplant <18 years of age between 1999 and 2020 with ≥1 year of follow-up data available. RESULTS: Our analysis included 3493 patients with a median time post-transplant of 6.7 years. There were 893 patients (25.6%) switched to monotherapy at least once with the remaining 2600 patients always on ≥2 ISDs. The median time on monotherapy after the first year post-transplant was 2.8 years (range 1.1-5.9 years). We found an adjusted hazard ratio (HR) of 0.65 (95%CI: 0.47-0.88) favoring monotherapy compared to ≥2 ISDs (p = 0.002). There were no meaningful differences in the incidence of secondary outcomes between groups, except for a lower rate of cardiac allograft vasculopathy in patients on monotherapy (HR 0.58, 95%CI: 0.45-0.74). CONCLUSIONS: For pediatric heart transplant recipients placed on monotherapy, immunosuppression with a single ISD after the first year post-transplant was noninferior to standard therapy with ≥2 ISDs in the medium term. CONDENSED ABSTRACT: Some children are switched to a single immunosuppressive drug (ISD) for various reasons after heart transplant, but outcomes associated with differences in immunosuppression are unknown for children. We assessed graft failure in children on a single ISD (monotherapy) compared to ≥2 ISDs in a cohort of 3493 children with a first heart transplant. We found an adjusted hazard ratio of 0.65 (95%CI: 0.47-0.88) favoring monotherapy. We concluded that for pediatric heart transplant recipients placed on monotherapy, immunosuppression with a single ISD after the first year post-transplant was non-inferior to standard therapy with ≥2 ISDs in the medium term.
