TRANSPLANTATION Hematopoietic cell transplantation (HCT)–specific comorbidity index: a new tool for risk assessment before allogeneic HCT

We previously reported that the Charlson Comorbidity Index (CCI) was useful for predicting outcomes in patients undergo-ing allogeneic hematopoietic cell trans-plantation (HCT). However, the sample size of patients with scores of 1 or more, captured by the CCI, did not exceed 35%. Further, some comorbidities were rarely found among patients who underwent HCT. Therefore, the current study was designed to (1) better define previously identified comorbidities using pretrans-plant laboratory data, (2) investigate addi-tional HCT-related comorbidities, and (3) establish comorbidity scores that were suited for HCT. Data were collected from 1055 patients, and then randomly divided into training and validation sets. Weights were assigned to individual comorbidi-ties according to their prognostic signifi-cance in Cox proportional hazard models. The new index was then validated. The new index proved to be more sensitive than the CCI since it captured 62 % of patients with scores more than 0 com-pared with 12%, respectively. Further, the new index showed better survival predic-tion than the CCI (likelihood ratio of 23.7 versus 7.1 and c statistics of 0.661 versus 0.561, respectively, P <.001). In conclu-sion, the new simple index provided valid and reliable scoring of pretransplant co-morbidities that predicted nonrelapse mortality and survival. This index will be useful for clinical trials and patient coun-seling before HCT. (Blood. 2005;106