Reevaluation of the Pretransplant Assessment of Mortality Score after Allogeneic Hematopoietic Transplantation

The Pretransplant Assessment of Mortality (PAM) score was developed in 2006 to predict risk of mortality after allogeneic hematopoietic cell transplantation (HCT). Transplant practices have evolved during the past decade, suggesting the need to reevaluate the performance of the PAM score. We used statistical modeling to analyze and recalibrate mortality based on overall PAM scores, its components, and conditioning regimen in a retrospective cohort of 1549 patients who had HCT from 2003 through 2009. PAM scores correlated with mortality, but the effect size was smaller in the current study than in previous studies. PAM scores also demonstrated a stronger association with mortality in patients who received myeloablative conditioning than in those who received reduced-intensity conditioning. In contrast to the original study, carbon monoxide diffusing capacity, serum alanine aminotransferase, and serum creatinine concentrations were no longer significantly associated with 2-year mortality, whereas patient and donor cytomegalovirus serology was associated with mortality in the current cohort. Based on our findings, we developed and tested a revised PAM score for clinicians to estimate survival after allogeneic HCT with myeloablative conditioning regimens for patients with hematologic malignancy. Prognostic models such as the PAM score should be updated and recalibrated periodically to accommodate changes in clinical practice.