Association between pre-transplant CONUT score and pneumonia risk after allogeneic stem cell transplantation in acute leukemia

The Controlling Nutritional Status (CONUT) score has been proposed as a simple tool for assessing nutritional and immunological status and has been associated with prognosis in various malignancies. This study aimed to assess the relationship between pre-transplant CONUT scores and pneumonia development within one year after allogeneic stem cell transplantation (allo-SCT) in patients with acute leukemia. In this retrospective single-center study, 158 patients who underwent allo-SCT for acute leukemia between 2013 and 2023 were included. Patients who developed pneumonia during their 1-year post-transplant follow-up were evaluated and their nutritional status was calculated using the CONUT score. The CONUT score was calculated from serum albumin, total cholesterol, and total lymphocyte count measured prior to transplantation. Pneumonia diagnosis was based on thoracic CT findings consistent with clinical symptoms (new infiltrate or consolidation), with microbiological confirmation when available. Pneumonia occurred in 40 patients (25.3%) within one year after transplantation. The one-year mortality rate was 42.5% (n = 17) in patients with pneumonia compared to 22.9% (n = 27) in those without pneumonia. Although mortality was higher among patients with pneumonia, no statistically significant association was found between pre-transplant CONUT scores and pneumonia development. To our knowledge, this is the first study to examine the association between pre-transplant CONUT scores and pneumonia risk after allo-SCT in acute leukemia patients. Our findings indicate no significant predictive value. The multifactorial etiology of pneumonia and the dynamic nutritional and immunological changes in this high-risk population may limit the usefulness of static nutritional indices such as the CONUT score in predicting infectious complications. Incorporating supplemental nutritional or immunological markers may improve risk assessment in this population.