A study of two different strategies for optimizing antibiotic therapy in intensive care unit (ICU) patients with pneumonia found that both provided high rates of appropriateness in empiric antibiotic selection, but one was better at reducing antibiotic overuse, researchers reported today in Open Forum Infectious Diseases.
In the study, researchers from the University of Michigan and the University of Kansas compared two strategies for selecting empirical antibiotic treatment in patients with hospital-acquired and ventilator-associated pneumonia (HAP/VAP) caused by gram-negative bacteria, which is a common infection in intensive care units and associated with high morbidity and mortality. Guidelines recommend administering two antipseudomonal agents, but they lack clear guidance on which antibiotics to use.
One strategy is to develop local antibiograms based on common pathogens and use the results to inform treatment strategies. The other is to base treatment on patient-specific risk factors, such as previous antibiotic use.
To compare the two, the researchers spent one period (2021) collecting respiratory cultures and reviewing patient charts from ICU patients at a tertiary care hospital in Michigan to develop optimal empiric antibiotic regimens based on local antibiograms and a risk factor-based algorithm. In the second period (2022), they hypothetically applied the strategies to patients to compare rates of appropriate therapy and antibiotic overuse.
Risk factor–based approach offers advantages
The analysis found that risk factor–based regimens had a higher appropriateness rate compared to regimens derived from antibiograms (89.9% vs 83.7%). Additionally, applying antibiogram-based regimens resulted in a higher prevalence of antibiotic overuse than a patient-specific risk factor–based approach (69.8% vs. 40.3%), with excess overuse driven by a higher frequency of unnecessary use of combination therapy.
"Both patient-specific risk factors and unit-specific combination antibiogram approaches were useful and can be applied in empiric antibiotic selection," the study authors wrote. "However, the patient-specific risk factor-based approach offers higher rate of appropriateness therapy and advantages in reducing the overuse of combination agents."