Real-World Experience with High- versus Low-Dose Polymyxin B for Pulmonary Infections: A Retrospective Cohort Study

Area of Science:

• Infectious Diseases
• Pharmacology
• Critical Care Medicine

Background:

• Polymyxin B (PMB) is vital for treating carbapenem-resistant Gram-negative pulmonary infections.
• Current real-world dosing of PMB is inconsistent.
• Clinical and economic impacts of varying PMB doses need investigation.

Purpose of the Study:

• To compare clinical efficacy, safety, and costs of high-dose versus low-dose intravenous Polymyxin B in adult patients.
• To evaluate real-world dosing practices and their outcomes.

Main Methods:

• Single-center retrospective cohort study of 235 adult patients with pulmonary infections.
• Patients received intravenous PMB between January 2020 and December 2024.
• Categorization into high-dose and low-dose groups based on real-world administration.

Main Results:

• Lower dose PMB was associated with significantly lower 28-day and 42-day all-cause mortality.
• No significant differences in clinical response rates or hospital length of stay were observed.
• While most adverse events were similar, higher frequency of non-significant adverse events in the high-dose group. Low-dose regimens significantly reduced drug costs, but total hospitalization costs were comparable.

Conclusions:

• Low-dose Polymyxin B (<1.5 mg/kg/day) with extended therapy may offer improved safety and lower mortality for pulmonary infections compared to high-dose regimens.
• Low-dose PMB demonstrated potential for cost savings in drug expenditure.
• Prospective studies are necessary to validate these findings and guide PMB dose optimization.