Clinical Outcomes and Medication Cost Analysis of Implementing an Intravenous-to-Oral Antibiotic Switch Program in Patients with Community-Acquired Pneumonia: A Case Study

Abstract

Background: Antimicrobial resistance is a global public health concern, including in Thailand. To address this issue, the Antimicrobial Stewardship Program (ASP) has been implemented to promote the rational use of antimicrobial agents. One of the strategies recommended by ASP is the conversion of antimicrobial administration from intravenous (IV) formulations to oral formulations, which supports appropriate antimicrobial use.

Objective: To study and evaluate clinical outcomes regarding the duration of intravenous (IV) antibiotic use, length of hospital stay, the rate of antibiotic switch from intravenous to oral administration, 28-day hospital readmission rate, 30-day post-discharge mortality rate. total antibiotic costs, and overall hospitalization expenses after implementing a decision-support form to guide physicians in switching from IV to oral antibiotics in patients with community-acquired pneumonia.

Methods: A retrospective study was conducted using medical records from U Thong Hospital. Data were compared before and after the implementation of the switching process during the same period (July 1 – December 31, 2023 and 2024). The study included inpatients aged 18 years and older who were diagnosed with community-acquired pneumonia, Sample size was calculated using the G*Power analysis program totaling 62 patients in each group who met the inclusion and exclusion criteria. Patients were divided into a group that switched to oral antibiotics and a group that continued IV administration. The collected data were analyzed using descriptive statistics, including frequency, percentage, and chi-square test. Data related to duration and cost were reported as medians. The distribution of data was assessed using the Kolmogorov-Smirnov test, which indicated non-normal distribution (p < 0.05); therefore, the Mann-Whitney U test was used for group comparisons.

Results: Following the implementation, the group that switched to oral antibiotics showed a statistically significant reduction in the median duration of IV antibiotic use and hospital stay (5 and 4 days, respectively; P = 0.026 and P = 0.022). The switching rate increased to 75.8% from 53.2%. There were no statistically significant differences in the 28-day readmission rate and the 30-day post-discharge mortality rate Although there was a slight increase in the median total antibiotic cost after the implementation compared to the period before (238.8 vs. 218.8 THB; P = 0.608), the overall hospitalization expenses were lower (3,654.4 vs. 4,125.4 THB; P = 0.119).

Conclusion: The implementation of the decision-support form to facilitate switching from IV to oral antibiotics in patients with community-acquired pneumonia helped reduce the duration of IV antibiotic use and hospital stay, increased the switching rate, and decreased overall hospitalization costs.