Hematopoietic cell transplantation comorbidity index (HCT-CI) is predictive of adverse events and overall survival in older allogeneic transplant recipients

Objectives: Our goal was to evaluate the ability of the hematopoietic cell transplantation comorbidity index (HCT-CI) to predict outcomes after allogeneic stem cell transplant (SCT) within the context of an older patient population, where multiple comorbidities are common. Materials and Methods: We performed a retrospective cohort study of SCT patients ≥ 50 years of age at our institution, identifying 59 patients with complete HCT-CI data collected prospectively. Results: HCT-CI category distribution in our sample was disproportionate, with almost half of patients having scores ≥ 3. High HCT-CI score (≥ 3 vs < 3) was associated with significantly inferior OS (median OS not reached for HCT-CI < 3 vs 14 months for HCT-CI ≥ 3; hazard ratio (HR) 2.2, p = 0.02). HCT-CI score was a better predictor of OS than age, performance status or conditioning intensity. When adjusted for disease relapse risk, HCT-CI score conferred a worse prognosis in the low risk group (HR 1.43, p = 0.03) but not in the intermediate/high risk group (HR 1.08, p = 0.65). NRM was low in the total sample (6% at one year) and was not associated with HCT-CI score. Grade 3-4 non-hematologic adverse events within the first 100. days after SCT were significantly more common in the higher HCT-CI groups (p = 0.02). Conclusions: In our older patient cohort with a high incidence of multiple comorbidities, HCT-CI score ≥ 3 was significantly associated with OS, particularly in the subset of patients with a low disease relapse risk.