# Evaluation of Antibiotic Use in Patients Admitted to a Hungarian Intensive Care Unit with Pneumonia and Sepsis: Retrospective Observational Before–After Study

## TL;DR

This study shows that an antibiotic stewardship program in a Hungarian ICU improved appropriate antibiotic use and slightly better outcomes for pneumonia and sepsis patients.

## Contribution

The study evaluates the impact of a local antibiotic stewardship program on antibiotic use and clinical outcomes in ICU patients with pneumonia and sepsis.

## Key findings

- Antibiotic stewardship increased guideline-adherent agent selection and combination therapy while reducing fluoroquinolone use.
- The program led to a significant decrease in the use of restricted antibiotics and slightly improved clinical outcomes like 30-day mortality and ICU length of stay.
- Multidrug-resistant pathogens were detected in a third of cases, leading to higher ICU costs.

## Abstract

Background: Early and adequate empiric antibiotic therapy is essential in the treatment of pneumonia and sepsis and may influence the clinical outcome. Aims and Objectives: This retrospective before–after study aimed to appraise the impact of a local Antibiotic Stewardship Program (ASP—written guidelines and antibiotic restriction) on antibiotic (AB) use and clinical outcomes in patients requiring intensive care due to pneumonia and sepsis. Methods: This study was conducted as a single-center, retrospective observational study in the intensive care unit (ICU) of a pulmonology department of a tertiary care center. Data were collected for the pre-intervention period between January 2018 and May 2022 and for the ASP period between June 2022 and March 2024. In addition to descriptive statistics and univariable methods, interrupted time series (ITS) analysis was used to assess AB use and length of stay in the ICU before and after ASP implementation, using a segmented linear regression with a fixed breakpoint and continuous (hinge) specification. Results: The patients admitted to the ICU with pneumonia and sepsis were mainly men (58/101, 57.4% and 84/128, 65.6%), the need for intensive care increased with age, and most of the patients belonged to 65+ age group in both study phases (69/101, 68.3% and 75/128, 58.6%). The majority of the patients had four or more comorbidities (58/101, 57.4% and 52/128, 40.6%). In-hospital mortality was relatively high (42.6% and 41.4%), with most of the patients losing their lives in the ICU (33/43, 76.7% and 37/53, 69.8%). Significant increase in guideline-adherent agent selection (34.5%) and use of combination therapy (35.0%) was observed, while the use of fluoroquinolones decreased significantly (−31.1%). In the after period, a significant decrease in the number of patients using restricted ABs (−53.3%) was observed. In one-third of these cases (10/34, 29.4% and 16/40, 40%), two to four multidrug-resistant pathogens (MDRs) were detected simultaneously, resulting in a significant increase in direct costs (10.5%) in the ICU. The inappropriate use of AB therapy was relatively low in the presence of MDRs in both phases (2/34, 5.9% and 6/40, 15%). In the ASP period, guideline adherence was associated with slightly better clinical outcomes (30-day mortality: −0.8%; length of stay: −22.6%) in pneumonia and sepsis. The ITS analyses after the ASP implementation showed a weak downward trend and before it a slight increasing trend. Conclusions: ASP implementation in the ICU resulted in a significant improvement in the appropriate use of ABs, and guideline adherence led to slightly better clinical outcomes. Our results suggest that ASP may offer improved antimicrobial resistance with a sustained long-term effect.