Association between the prognostic nutritional index and early mortality of AML patients after allogeneic HSCT: a retrospective cohort analysis.

[BACKGROUND] Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is an effective treatment for Acute Myeloid Leukemia (AML). The pre-transplantation Prognostic Nutritional Index (PNI) plays a critical role in determining patient prognosis, however, its correlation with mortality within 180 days after SCT is currently unclear.

[OBJECTIVE] This study aimed to investigate the association between PNI and mortality within 180 days among AML patients who underwent HSCT.

[METHODS] We conducted a cohort study by retrospectively collecting data from AML patients who underwent HSCT. The PNI was calculated and recorded as serum albumin (g/L) + 5 × peripheral blood lymphocyte count (10/L) using pre-transplantation laboratory data. Patients were divided into three groups based on PNI tertiles. A Cox proportional hazards model was employed to explore the nonlinear relationship between PNI and mortality in these patients. The correlation between pre-transplant PNI and hematopoietic reconstitution, as well as complications such as gastrointestinal bleeding, fever, and graft-versus-host disease (GVHD), was also analyzed.

[RESULTS] This retrospective cohort study included 477 adult patients with AML. The mean age of the patients was 37.4 ± 11.8 years, with males accounting for 55.6%. The vast majority (79.5%) of patients received transplants from related donors. Among those patients, 13.2% died within 180 days after transplantation. Patients with PNI T1 (30.2-44.6) had a significantly higher adjusted hazard ratio (HR) for mortality (1.52; 95% confidence intervals (CI), 1.17-1.98;  = 0.002) compared with PNI T2 (44.7-49.1), while PNI T3 (49.2-102.6) did not show increased risk (HR, 1.05; 95% CI, 0.81-1.35;  = 0.732). A PNI threshold of 46 marked a significant decrease in mortality risk with increasing PNI values, suggesting a critical point for nutritional intervention. Above this threshold, PNI showed no further prognostic value, indicating a plateau effect. These findings underscore PNI's potential in guiding targeted nutritional support to improve post-transplant outcomes.

[CONCLUSIONS] The PNI exhibits a L-shaped association with 180-day mortality in AML patients post-HSCT, emerging as a significant predictor with a critical threshold identified at PNI 46. Below this threshold, declining PNI values correlate with increased mortality risk, underscoring its clinical utility in driving nutritional interventions to enhance post-transplant survival outcomes.