Severe bacterial infection in thalassemia patients: prevalence, predisposing factors, causative organisms and outcomes

Introduction Thalassemia is one of the most common genetic blood disorders globally. Bacterial infections remain a major cause of death among affected patients. To determine prevalence, predisposing factors, causative organism, and outcomes of severe bacterial infection in thalassemia patients. Methods This retrospective study analyzed data from the Thalassemia Registry of the Division of Hematology, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University (September 2013–September 2023). Thalassemia patients aged >15 years were included. Risk factors for severe bacterial infection were identified using multivariate logistic regression. Severe bacterial infection was defined as community-acquired involving a major organ, requiring parenteral antibiotics and/or surgery, and associated with a National Early Warning Score (NEWS) > 4. Results A total of 208 patients were enrolled (mean age 45.3 ± 16.0 years; 62.0% female; 56.7% transfusion-dependent; 36.1% splenectomy). Severe bacterial infection occurred in 43 patients (20.7%). Primary bacteremia was the most common (23.2%), with Klebsiella pneumoniae (20.9%) and Escherichia coli (13.9%) as the leading pathogens. Infection-related mortality rate was 9.3%. Significant risk factors included hematocrit 10 years (OR = 2.46; 95% CI 1.07–5.69; p = 0.035), diabetes mellitus (OR = 10.42; 95% CI 2.21–49.12; p = 0.03), and liver hemochromatosis (OR = 3.76; 95% CI 1.64–8.63; p = 0.002). Conclusion Severe bacterial infections affected 20.7% of thalassemia patients in this cohort, mainly bacteremia due to Klebsiella pneumoniae and Escherichia coli. Major risk factors were severe anemia, prolonged splenectomy, diabetes mellitus, and iron overload with liver hemochromatosis.