Influence of anaemia in severely injured patients on mortality, transfusion and length of stay: an analysis of the TraumaRegister DGU(®)

PURPOSE: Anaemia is one of the leading causes of death among severely injured patients. It is also known to increase the risk of death and prolong the length of hospital stay in various surgical groups. The main objective of this study is to analyse the anaemia rate on admission to the emergency department and the impact of anaemia on in-hospital mortality. METHODS: Data from the TraumaRegister DGU(®) (TR-DGU) between 2015 and 2019 were analysed. Inclusion criteria were age ≥ 16 years and most severe Abbreviated Injury Scale (AIS) score ≥ 3. Patients were divided into three anaemia subgroups: no or mild anaemia (NA), moderate anaemia (MA) and severe anaemia (SA). Pre-hospital data, patient characteristics, treatment in the emergency room (ER), outcomes, and differences between trauma centres were analysed. RESULTS: Of 67,595 patients analysed, 94.9% (n = 64,153) exhibited no or mild anaemia (Hb ≥ 9 g/dl), 3.7% (n = 2478) displayed moderate anaemia (Hb 7–8 g/dl) and 1.4% (n = 964) presented with severe anaemia (Hb < 7 g/dl). Haemoglobin (Hb) values ranged from 3 to 18 g/dl with a mean Hb value of 12.7 g/dl. In surviving patients, anaemia was associated with prolonged length of stay (LOS). Multivariate logistic regression analyses revealed moderate (p < 0.001 OR 1.88 (1.66–2.13)) and severe anaemia (p < 0.001 OR 4.21 (3.46–5.12)) to be an independent predictor for mortality. Further significant predictors are ISS score per point (OR 1.0), age 70–79 (OR 4.8), age > 80 (OR 12.0), severe pre-existing conditions (ASA 3/4) (OR 2.26), severe head injury (AIS 5/6) (OR 4.8), penetrating trauma (OR 1.8), unconsciousness (OR 4.8), shock (OR 2.2) and pre-hospital intubation (OR 1.6). CONCLUSION: The majority of severely injured patients are admitted without anaemia to the ER. Injury-associated moderate and severe anaemia is an independent predictor of mortality in severely injured patients.