Comorbidities in transplant recipients with acute myeloid leukemia receiving low-intensity conditioning regimens: an ALWP EBMT study

Association of individual comorbidities with outcomes in allogeneic hematopoietic cell transplantation from unrelated adult donors versus unrelated cord blood: A study on behalf of the Donor/Source and Transplant Complications Working Groups of the Japanese Society for Transplantation and Cellular Therapy

We retrospectively evaluated the effect of 17 individual comorbidities, defined by the hematopoietic cell transplantation (HCT)-specific comorbidity index, on non-relapse mortality (NRM) and overall survival (OS) in 9531 patients aged between 16 and 70 years who underwent their first allogeneic HCT from 8/8 and 7/8 allele-matched unrelated donors (8/8 and 7/8 MUDs) or single-unit unrelated cord blood (UCB) between 2011 and 2020 using data from a Japanese registry database. In the multivariate analysis, infection (adjusted hazard ratio [HR], 1.62, 95% confidence interval [CI], 1.33-1.99 for 8/8 and 7/8 MUDs; adjusted HR, 1.33, 95%CI, 1.12-1.58 for UCB) and moderate/severe hepatic comorbidity (adjusted HR, 1.57, 95%CI, 1.04-2.38 for 8/8 and 7/8 MUDs; adjusted HR, 1.53, 95%CI, 1.09-2.15 for UCB) had a significant impact on NRM in both donor groups. Cardiac comorbidity (adjusted HR, 1.40, 95%CI, 1.08-1.80), mild hepatic comorbidity (adjusted HR, 1.22, 95%CI, 1.01-1.48), rheumatologic comorbidity (adjusted HR, 1.67, 95%CI, 1.11-2.51), renal comorbidity (adjusted HR, 2.44, 95%CI, 1.46-4.09), and severe pulmonary comorbidity (adjusted HR, 1.40, 95%CI, 1.11-1.77) were significantly associated with an increased risk of NRM but only in UCB recipients. Renal comorbidity had the strongest impact on poor OS in both donor groups (adjusted HR, 1.73, 95%CI, 1.10-2.72 for 8/8 and 7/8 MUDs; adjusted HR, 2.24, 95%CI, 1.54-3.24 for UCB). Therefore, unrelated donor selection should be taken into consideration along with the presence of specific comorbidities, such as cardiac, rheumatologic, renal, mild hepatic, and severe pulmonary comorbidities.

The sum of the parts: what we can and cannot learn from comorbidity scores in allogeneic transplantation

Allogeneic hematopoietic cell transplantation (alloHCT) requires the comprehensive evaluation of patients across multiple dimensions. Among the factors considered, comorbidities hold great significance in the pretransplant assessment. As many as 40% of alloHCT recipients will have a high burden of comorbidities in contemporary cohorts. To ensure a standardized evaluation, several comorbidity scores have been developed; however, they exhibit variations in properties and performance. This review examines the strengths and weaknesses associated with these comorbidity scores, critically appraising these models and proposing a framework for their application in considering the alloHCT candidate. Furthermore, we introduce the concept that comorbidities may have specific effects depending on the chosen transplantation approach and outline the findings of key studies that consider the impact of individual comorbidities on alloHCT outcomes. We suggest that a personalized transplantation approach should not rely solely on the overall burden of comorbidities but should also take into account the individual comorbidities themselves, along with other patient, disease, and transplantation-related factors.

The Simplified Comorbidity Index predicts non-relapse mortality in reduced-intensity conditioning allogeneic haematopoietic cell transplantation

Comorbidity assessment before allogeneic haematopoietic cell transplantation (allo-HCT) is essential for estimating non-relapse mortality (NRM) risk. We previously developed the Simplified Comorbidity Index (SCI), which captures a small number of 'high-yield' comorbidities and older age. The SCI was predictive of NRM in myeloablative CD34-selected allo-HCT. Here, we evaluated the SCI in a single-centre cohort of 327 patients receiving reduced-intensity conditioning followed by unmanipulated allografts from HLA-matched donors. Among the SCI factors, age above 60, mild renal impairment, moderate pulmonary disease and cardiac disease were most frequent. SCI scores ranged from 0 to 8, with 39%, 20%, 20% and 21% having scores of 0-1, 2, 3 and ≥4 respectively. Corresponding cumulative incidences of 3-year NRM were 11%, 16%, 22% and 27%; p = 0.03. In multivariable models, higher SCI scores were associated with incremental risks of all-cause mortality and NRM. The SCI had an area under the receiver operating characteristic curve of 65.9%, 64.1% and 62.9% for predicting 1-, 2- and 3-year NRM versus 58.4%, 60.4% and 59.3% with the haematopoietic cell transplantation comorbidity index. These results demonstrate for the first time that the SCI is predictive of NRM in patients receiving allo-HCT from HLA-matched donors after reduced-intensity conditioning.