Phase angle as a screening tool for mortality risk among hematopoietic stem cell transplanted adult patients

Mortality among adult patients undergoing hematopoietic stem cell transplantation (HSCT) is high, especially within the first 100 days after the event. Therefore, identifying prognostic factors would be useful as screening tools to protect patients at risk throughout early intervention. In our previous work, the standardized phase angle (SPA) was explored as a useful indicator of survival and nutritional status among children and adolescent within the first 180 days after HSCT. The aim of this study was to evaluate the SPA and the arm muscle area (AMA) as prognostic indicators of mortality and nutritional status among adults in the same population.

This study was conducted with 29 adult patients undergoing allogeneic HSCT and 28 controls. Anthropometric assessment as well as body composition and laboratory data were analyzed. The phase angle was standardized according to reference values for healthy population. The correlation of SPA and AMA with other variables was verified and sensibility and specificity were tested by constructing ROC curves considering mortality and nutritional status as outcomes. Kaplan-Meier analysis was applied to calculate survival considering the cut-off points found in ROC curves. Chi-squared test and Kappa coefficient were used for evaluate the agreement among methods of nutritional assessment.

SPA presented a predictive value for mortality and nutritional status considering the cut-off point at -0.19. In fact, the mortality incidence was higher among patients with values below the cut-off point for SPA as compared to the ones with SPA above this value up to 90 days after the HSCT. Regarding to AMA, mortality was higher using the values bellow P15 (percentile 15) as reference. The average SPA decreased after the beginning of conditioning and after the HSCT, while the decrease of AMA was observed only 90 days after the transplant.

In this study SPA was confirmed as a prognostic tool for adult HSCT patients. In addition, it seems that SPA is more sensitive to detect structural body changes among the transplanted patients as compared to AMA. More studies are needed to confirm it as a tool to screen patients at risk of mortality for early intervention.