Specific Trends in Blood Utilization During the COVID-19 Pandemic: A Retrospective Analysis of a Hungarian Clinical Centre

<b>Background/Objectives:</b> The COVID-19 pandemic significantly disrupted healthcare systems and blood supply chains. This study aimed to analyze blood transfusion trends across three distinct clinical departments in a Hungarian tertiary care clinical center and to examine the relationship between these trends and the pandemic waves. <b>Methods:</b> A retrospective analysis of hospitalization and transfusion data from the Departments of Anesthesiology and Intensive Therapy, Surgery, and the Division of Hematology at the University of Pécs Clinical Centre was performed between 1 January 2020, and 31 December 2023. Generalized additive models were employed to assess the association between available predictors and the odds and volume of red blood cell transfusions. <b>Results:</b> At the Department of Anesthesiology and Intensive Therapy, the median weekly ratio of transfused patients fell from 50% (pre-pandemic) to 9.76% (third wave of pandemic). COVID-19 diagnosis was associated with lower odds of receiving transfusion (OR: 0.23) and with a lower incidence rate ratio of transfused red blood cells (IRR: 0.22). At the Department of Surgery, the median weekly ratio of transfused patients was consistently low and stable (9-10%) throughout the study period. The number of patients remained relatively stable at the Division of Hematology during the study period, expressing a higher odds of receiving transfusion during the second (OR: 2.63) and fourth (OR: 1.52) pandemic waves. <b>Conclusions:</b> The pandemic's impact on transfusion practice, driven by indirect various consequences of patient redirection and protocol modifications, was most expressed at the Department of Anesthesiology and Intensive Therapy. Similar changes in transfusion practice may be anticipated in the event of another pandemic outbreak.