Hematological Predictors of Extramedullary Hematopoiesis and Their Association with Radiological Disease Burden and Surgical Intervention in Patients with Β-Thalassemia

Abstract

Background: Extramedullary hematopoiesis (EMH) is a compensatory mechanism to chronic anemia and ineffective erythropoiesis and it is an important complication of β-thalassemia. The clinical relevance ranges from no apparent lesions on the X-ray to large paraspinal masses compressing the nervous system, which must be surgically removed. The identification of hematological abnormalities associated with EMH might help to identify patients at potential risk for significant radiological disease earlier.

Objective: To determine the hematological predictors of extramedullary hematopoiesis and evaluate their association with radiological disease burden and the requirement for surgical intervention in patients with β-thalassemia.

Methods: This study was descriptive, analytical in nature and included 78 patients of β-thalassemia, who were treated at Bacha Khan Medical College, Mardan from March 25, 2025 to September 25, 2025. Demographic and clinical data, transfusion history, prior splenectomy, haematological parameters, biochemical parameters, radiological features of EMH and management were documented. Patients with and without EMH were compared and factors related to radiological disease burden and surgical intervention were evaluated. Multivariable logistic regression was used to determine independent predictors of EMH. A p value < 0.05 was defined as being statistically significant.

Results: Extramedullary hematopoiesis was identified in 32 (41.0%) of 78 patients. Patients with EMH had significantly lower mean hemoglobin levels than those without EMH (7.5 ± 1.2 vs 8.8 ± 1.4 g/dL; p<0.001), together with higher reticulocyte counts (8.4 ± 3.0% vs 5.7 ± 2.6%; p<0.001), RDW (20.4 ± 3.3% vs 17.8 ± 3.1%; p=0.001), and LDH concentrations (p=0.002). Previous splenectomy and irregular transfusion were also significantly associated with EMH. Among patients with EMH, 9 (28.1%) had severe radiological disease and 11 (34.4%) required surgical intervention. Spinal canal extension, neurological manifestations, large lesions, and severe radiological burden were significantly associated with surgery. On multivariable analysis, lower hemoglobin, higher reticulocyte count, previous splenectomy, and irregular transfusion remained independently associated with EMH.

Conclusion: Persistent anemia and increased erythropoietic activity were strongly associated with extramedullary hematopoiesis in β-thalassemia. Lower hemoglobin and elevated reticulocyte counts may help identify patients at increased risk, while severe radiological involvement and neurological compression appear particularly relevant to the requirement for surgical treatment.