Emergency department presentations with mammalian bite injuries: Risk factors for admission and surgery

Objectives: The incidence of animal bite injuries in Australia is high. There is currently no established method for reliably predicting whether a patient with a bite injury will require admission to hospital or surgery. 

Design: A retrospective audit of mammalian bite injuries at seven major hospitals in Melbourne, Victoria, over a 2-year period. The associations between each predictor and outcome of interest were analysed with univariate and multiple regression analyses. 

Setting: Seven major hospitals in Melbourne, Victoria: the Alfred Hospital, Austin Hospital, Frankston Hospital, Monash Medical Centre, Royal Melbourne Hospital, St Vincent’s Hospital and Western Hospital. 

Participants: Patients presenting to emergency departments with mammalian bite injuries. 

Main outcome measures: Hospital admission, intravenous antibiotic therapy, surgery, reoperation, readmission. 

Results: We identified 717 mammalian bite injuries. The mean age of the patients was 36.5 years (median, 34 years; range, 0-88 years), with an equal number of males and females. The overall rate of hospital admission was 50.8%, and the mean length of stay was 2.7 days. Intravenous antibiotics were administered in 46% of cases; surgery was undertaken in 43.1% of cases. The re-operation rate was 4.5%, the re-admission rate was 3%. 

Conclusions: Our study provides a detailed epidemiological analysis of animal bite injuries at seven major hospitals in Victoria. Risk factors for hospitalisation and surgery may assist in identifying patients who require admission and surgical intervention.