Comorbidity Indexes and Allogeneic Stem Cell Transplantation (SCT).

Despite recent advances, mortality rates after allogeneic hematopoietic cell transplantation remain high and cannot be accurately predicted. During the last years several reports from the Seattle group suggest the use of comorbidity indexes (CI) to provide valid and reliable scoring of pre-transplant comorbidities that predicted non-relapse mortality (NRM) and survival [Blood 2004 (CCI), 2005 (HCT-CI) & Ann Int Med 2006 (PAM)). However whether such indexes could be applied by other groups, and if one index better predicts NRM than another, is unknown yet. Patients undergoing their first allogeneic SCT at Saint-Louis between April 2004 and December 2005 were considered. A total of 183 patients were first included in the study (median age 31, range [4–64], 41% from unrelated donors, 87% intermediate or high-risk diseases). Survival curves were estimated using Kaplan-Meier estimator, and cumulative incidence curves of NRM, treating relapse as competing event. The likelihood ratio statistics in proportional hazards models was computed for each index, with its associated P-value, as a measure of association between the comorbidity indexes collapsed into risk groups and the outcomes. Discriminative performance of comorbidity indexes was then evaluated by the c-index. Standard errors of c-indexes were computed from that of Somers’ D_xy rank correlation coefficient. P-values for comparison of c-indexes were obtained using a nonparametric bootstrap procedure. Using CCI, 21% of our patients had indexes of 1 or more; median HCT-CI was 1; and median PAM score was 24. The discriminative properties of the 3 CI were rather low in our patient population with c-index of 0.54, 0.49 and 0.57 for the CCI, HCT-CI and PAM indexes, respectively. Comparisons of patients- and transplant-characteristics between our and Seattle group’s cohorts however reveal significant differences with more cord blood HCT and HCT for Fanconi anemia in St Louis. Finally direct comparison of scoring items revealed that, unrelated HCT, renal function, and lung function (PFTs) had however similar impact on NRM and OS in our cohort. Additional analyses including patients transplanted in 2006 are underway.