Anaerobe coverage is important for the prognosis of pyogenic liver abscess: A population-based study in Korea

Background: Gram-negative bacteria such as Klebsiella pneumoniae and Escherichia coli are the most common cause of pyogenic liver abscess (PLA). We investigated whether the use of anaerobic-covering antibiotics is essential for the treatment of pyogenic liver abscess.

Methods: We analyzed the Health Insurance Review and Assessment Service data in Korea between 2007 and 2017. We classified PLA into two groups: a group using antibiotics that inhibited only aerobic strains (anaerobe (-) group) and a group using antibiotics that inhibited both aerobic and anaerobic strains (anaerobe (+) group). The primary outcome was the difference in in-hospital mortality between the two groups.

Results: During this period, a total of 30,690 PLA patients were obtained. There were 6733 patients in the anaerobe (-) group and 23,957 patients in the anaerobe (+) group. In-hospital mortality was significantly lower in the anaerobe (+) group than the anaerobe (-) group (7.9% vs. 15.6%, p < 0.001). In multivariate analysis, the use of anaerobic antibiotics reduced the in-hospital mortality by 42% (odds ratio 0.42, 95% confidence interval 0.38-0.46, p < 0.001) after adjusting for age and comorbidities. Furthermore, the improvement of in-hospital mortality was present regardless of the presence of cancer or diabetes.

Conclusion: The use of broad-spectrum empirical antibiotics covering anaerobic strains is important for the treatment of pyogenic liver abscess.