Outcomes associated with use of makyokansekito, a Japanese herbal kampo medicine, in outpatients with community-acquired pneumonia: A retrospective cohort study.

Introduction: Although selected patients with community-acquired pneumonia (CAP) can be treated in outpatient settings, some exhibit an insufficient response to initial outpatient treatment resulting in subsequent hospitalizations. Laboratory and animal studies have demonstrated that makyokansekito, a Japanese herbal kampo medicine, can alleviate lung damage and inflammation. However, its clinical effectiveness in adult patients with CAP has not been evaluated. Methods: Using the commercially available JMDC health insurance claims database (Tokyo, Japan), we identified outpatients with CAP between April 2012 and April 2022. Patients were classified into those who received or did not receive makyokansekito on the day of diagnosis. The primary outcome was hospitalization within 30 days. The secondary outcomes included antibiotic treatment duration and total medical costs. Multivariate regression analyses were used to compare the outcomes between the two groups. Results: Among 76,177 eligible patients, 273 and 75,904 were classified into the makyokansekito and non-makyokansekito groups, respectively. After adjustment, the proportions of hospitalized patients in the makyokansekito and non-makyokansekito groups were 3.0 and 3.4%, respectively, with a difference of -0.4% (95% confidence interval [CI], -2.5% to 1.8%; Conclusion: The use of makyokansekito in outpatients with CAP was not associated with a reduction in hospitalization.