Replicated Risk Index of Patient Functional Status Prior to Allogeneic Hematopoietic Cell Transplantation Predicts Healthcare Utilization and Survival

Abstract

Poor physical functioning is associated with adverse outcomes after allogeneic hematopoietic cell transplantation (alloHCT). Analytic tools to predict mortality in alloHCT recipients include the HCT Comorbidity Index (HCT-CI) based on comorbidities and the Disease Risk Index (DRI) based on disease and disease status. We developed and replicated a risk model for overall survival (OS), early mortality (ie, death from any cause at or before day +100), initial hospital length of stay (LOS), and percentage of inpatient days within the first year post-alloHCT. In this study, we incorporated a physical therapy (PT) assessment with the HCT-CI and DRI to improve outcome predictions. The well-defined and feasible measure of functional status for assessing risk includes (1) the number of sit-to-stands performed in 30 seconds, (2) performance of 25 step-ups on the right/left side with (3) oxygen saturation recovery and (4) heart rate recovery, (5) weight-bearing ability, (6) assistance with ambulation, (7) motor and grip strength, (8) sensory and coordination impairment (eg, self-reported peripheral neuropathy, imbalance), (9) self-reported pain, and (10) limited endurance (ie, inability to complete step-ups and/or sit-to-stands). Our training cohort (TC) included 349 consecutive alloHCT recipients at Roswell Park treated between 2010 and 2016 and a subsequent replication cohort (RC; n = 163) treated between 2016 and 2019. Four of the 10 metrics-self-reported pain, limited endurance, self-reported neuropathy, and <10 sit-to-stands in 30 seconds-were identified as significant predictors and were included in the multivariable models with the HCT-CI and DRI to create a new risk index (HCT-PCDRI: HCT-physical, comorbidity, and DRI) for outcomes. Models were tested in the RC. Shorter OS was associated with self-reported pain, limited endurance, higher HCT-CI, and higher DRI. At a median follow-up of 34 months, the 3-year OS based on the HCT-PCDRI was 30% for the very-high-risk group, 54% for the high-risk group, 49% for the intermediate-risk group, and 80% for the low-risk group. The number of patients identified as very high risk increased from 55 using HCT-CI alone to 120 with the new HCT-PCDRI, whereas the number in the low-risk group decreased from 91 to 45. Early mortality and a higher percentage of inpatient days within the first year post-alloHCT (a proxy for poor quality of life and high healthcare utilization) were associated with self-reported pain, higher HCT-CI, and higher DRI. A shorter initial LOS (ie, initial low healthcare utilization) was associated with performance of >10 sit-to-stands in 30 seconds, no self-reported neuropathy, and lower HCT-CI. These PT metrics combined with the HCT-CI and DRI created the HCT-PCDRI, which resulted in more patients being categorized accurately as high risk versus low risk. The HCT-PCDRI results were replicated in an independent cohort. Pre-alloHCT PT metrics with self-reported symptoms (pain and neuropathy) were associated with survival post-alloHCT and prolonged hospital LOS. The HCT-PCDRI scoring system for risk stratification of alloHCT recipients more accurately identifies patients at potential risk of poor outcomes. The HCT-PCDRI can be tested in <15 minutes to identify patients for intervention before or during treatment to potentially improve outcomes.

Keywords: Allogeneic HCT; Physical functioning,; Risk index; comorbidity.