Title: Increased Mortality in Patients Requiring Blood Transfusion During Hospitalisation for Acute Pulmonary Embolism
Abstract: Introduction: The impact of red blood cell (RBC) transfusions in patients with acute pulmonary embolism (PE) and anaemia is not known. This study investigates the impact of RBC transfusions on short and long-term mortality in acute PE. Methods: Data was collected retrospectively from a tertiary institution for all patients (n = 1426) admitted with acute PE from 2000 to 2012. Patients’ haemoglobin levels during admission, as well as any details of RBC transfusions, were recorded. 327 patients were excluded due to missing data on either admission or subsequent haemoglobin level. The primary outcome was all-cause mortality at 6-month. Secondary outcomes included all-cause in-hospital mortality and at 30-day. Mortality outcomes were tracked using a state-wide death database and analysed using multivariable regression modelling to compare in-hospital, 30-day and 6-month mortality. Results: A total of 1099 patients were included in the study, of whom 71 patients received RBC transfusion during admission. Mean haemoglobin on admission for the RBC transfusion group was significantly lower compared to the group that did not receive transfusion (94 ± 16 g/L vs 131 ± 18 g/L, p < 0.001). All-cause mortality for patients receiving RBC transfusion was 10%, 18%, and 38% at discharge, 30-day, and 6-month respectively. Multivariable analyses, which included adjusting for impact of haemoglobin levels, revealed RBC transfusion to be an independent predictor of 30-day mortality (odds ratio 2.43, 95% confidence interval [CI] 1.09-5.44, p = 0.03) and 6-month mortality (hazard ratio 1.68, 95% CI 1.03-2.75, p = 0.04). Conclusion: RBC transfusion is associated with an increased risk of short-term and long-term mortality in patients hospitalised with acute PE.