Antibiotic prescribing in general medical and surgical specialties: a prospective cohort study

Background: Qualitative work has described the differences in prescribing practice across medical and surgical specialties. This study aimed to understand if specialty impacts quantitative measures of prescribing practice. Methods: We prospectively analysed the antibiotic prescribing across general medical and surgical teams for acutely admitted patients. Over a 12-month period (June 2016 – May 2017) 659 patients (362 medical, 297 surgical) were followed for the duration of their hospital stay. Antibiotic prescribing across these cohorts was assessed using Chi-squared or Wilcoxon rank-sum, depending on normality of data. The t-test was used to compare age and length of stay. A logistic regression model was used to predict escalation of antibiotic therapy. Results: Surgical patients were younger (p<0.001) with lower Charlson Comorbidity Index scores (p<0.001). Antibiotics were prescribed for 45% (162/362) medical and 55% (164/297) surgical patients. Microbiological results were available for 26% (42/164) medical and 29% (48/162) surgical patients, of which 55% (23/42) and 48% (23/48) were positive respectively. There was no difference in the spectrum of antibiotics prescribed between surgery and medicine (p=0.507). In surgery antibiotics were 1) prescribed more frequently (p=0.001); 2) for longer (p=0.016); 3) more likely to be escalated (p=0.004); 4) less likely to be compliant with local policy (p