Expanded Comorbidity Definitions Improve Application of the Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI) for Children and Young Adults with Non-Malignant Diseases Receiving Allogeneic Hematopoietic Cell Transplantation

Introduction: Allogeneic hematopoietic cell transplantation (HCT) can be employed as curative therapy for many non-malignant diseases but there is risk of transplant related complications. Pre-HCT, patient-specific factors can help inform risk using the HCT comorbidity index (HCT-CI); however, it can be difficult to apply in children and young adults, where assessment of organ function differs from those defined by the HCT-CI. We aimed to supplement the HCT-CI with pediatric-specific comorbidity definitions to broaden the use of the HCT-CI for pediatric & young adult patients with non-malignant diseases. Methods: Patients 95th percentile for Results: 2,815 patients received allogeneic HCT for non-malignant diseases (25.8% aplastic anemia, 26.5% immune deficiency, 18.2% hemoglobinopathies, 29.5% other) at a median age of 6 ( In multivariable analysis, comorbidities with pediatric-specific definitions demonstrated increased hazards of death, including in underweight patients (HR 1.55, 95% confidence interval (CI) 1.18-2.04), those with history of mechanical ventilation (HR 1.85, 95%CI 1.39-2.48), mild renal disease by eGFR (HR 1.49, 95%CI 1.11-2.0), or moderate/severe renal disease by eGFR (HR 2.04, 95%CI 1.1-3.26). Therefore, comorbidities were expanded to include these definitions in the Expanded HCT-CI. Expanding the comorbidity definitions increased the number of patients identified as having pre-HCT comorbidities: 35% were categorized with scores of 0, 32% with scores of 1-2, and 33% with scores of ≥3. Figure 1 shows the expanded comorbidity definitions and effect on OS. Arrhythmia and Psychiatric diseases were noted to have HR Conclusion: Modifications to definitions in the HCT-CI can create a pre-HCT risk tool that more broadly classifies organ dysfunction for children & young adults. By expanding the comorbidity definitions, 24% more patients were re-categorized as having at least 1 comorbidity, allowing for better assessment of pre-HCT risk. This expanded HCT-CI performs as well as the HCT-CI but is more broadly applicable to children & young adults with non-malignant diseases and can aid physicians in pre-HCT counseling. Download : Download high-res image (623KB) Download : Download full-size image Disclosures Schiller: Johnson & Johnson: Current equity holder in publicly-traded company; Karyopharm: Research Funding; Sangamo: Research Funding; AstraZeneca: Consultancy; Amgen: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; Agios: Consultancy, Research Funding, Speakers Bureau; Incyte: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Research Funding; Ono Pharma: Consultancy; Celgene: Research Funding, Speakers Bureau; Sanofi: Speakers Bureau; Gilead: Speakers Bureau; Stemline: Speakers Bureau; Onconova: Research Funding; Samus: Research Funding; Regimmune: Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Cyclacel: Research Funding; Daiichi Sankyo: Research Funding; Deciphera: Research Funding; DeltaFly: Research Funding; Bristol-Myers Squibb: Current equity holder in publicly-traded company, Research Funding; Forma: Research Funding; FujiFilm: Research Funding; Gamida: Research Funding; Genentech-Roche: Research Funding; Geron: Research Funding; Jazz Pharmaceuticals: Research Funding; Kite Pharma: Research Funding; Mateon: Research Funding; MedImmune: Research Funding; Tolero: Research Funding; Trovagene: Research Funding; Kaiser Permanente: Consultancy; Celator: Research Funding; Constellation: Research Funding; Astellas Pharma: Honoraria, Research Funding; Ariad: Research Funding; Actinium: Research Funding; Abbvie: Research Funding. Stadtmauer: Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Novartis, Onyx Pharmaceuticals, an Amgen subsidiary, Takeda Oncology: Consultancy. Pasquini: Bristol Myers Squibb: Consultancy; BMS: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Amgen: Other; Novartis: Research Funding; Kite: Research Funding. Thakar: Infectious Disease Research Institute: Consultancy. Sorror: Jazz Pharmaceutical: Other: Honorarium for Advisory role. .