Background and importance Antibiotics are widely prescribed in the emergency department (ED). Around 30–60% of antibiotic prescriptions in the ED are inappropriate; this fact is associated with an increase in length of hospital stay and is a public health problem. In this context, the ED becomes a key point for antibiotic optimisation.

Aim and objectives The objectives of the study were to determine the frequency and type of inappropriate prescriptions of antibiotic therapy (AT) in the ED and to assess the impact in terms of increase in hospital stay, readmissions and 30 day mortality after the event.

Material and methods This was a descriptive, observational, retrospective, multidisciplinary study authorised by the hospital research commission. A cross sectional serial point prevalence study of all antibiotic prescriptions for patients under observation in the ED between January and March 2020 was conducted. The appropriateness of the prescription was evaluated by specialists from emergency medicine and clinical pharmacists, according to the centre’s infection guidelines (CIG). Demographic variables, comorbidity and site of infection were checked with the electronic medical record (HPHCIS V.3.8). SPSSV.23 software was used for data analysis with centralisation and frequency measurements for descriptive data and the χ² test for inference.

Results A total of 192 AT were administrated to a total of 168 patients (52% men), mean age 65 (SD 20) years and 68.5% had a Charlson index ≥2. The three main site of infection were respiratory (53%), urinary (19%) and intra-abdominal (12%). 39.6% of the antibiotic prescriptions were assessed as inappropriate. Inappropriateness was classified and distributed as:

• Unnecessary, no signs of infection: 3.3% of AT prescriptions

• Not active for the expected aetiology: 9.8%

• Appropriate, but wrongly dosed: 4%

• Appropriate, but not recommended according to the CIG: 22.8%.

The indication with the highest degree of inappropriateness was urinary infections, with 19 of 31 AT prescriptions being inappropriate. Inappropriate prescription was not found to be a factor related to an increase in hospital stay (OR 1.39; 95% CI 0.77 to 2.50; p=0.269), readmissions (OR 0.751; 95% CI 0.35 to 1.59; p=0.455) or mortality (OR 1.40; 95% CI 0.87 to 22.86; p=0.809).

Conclusion and relevance In general, CIG were followed because almost two-thirds of AT were appropriate. Furthermore, inappropriate AT prescriptions did not lead to an increase in hospital stays, or readmissions or mortality. The inappropriateness of the AT results may be considered for the development of antibiotic optimisation strategies.

Conflict of interest No conflict of interest