Objective
Maoto is a traditional Japanese
Kampo formula used to treat
influenza. However, clinical evidence for
maoto has been limited to small-scale studies of its effect in alleviating symptoms. The present study evaluated whether or not the addition of
maoto to a
neuraminidase inhibitor was associated with a reduction in hospitalization following
influenza. Methods Using the JMDC Claims Database, we identified outpatients <60 years old who were diagnosed with
influenza by an
antigen test from September 2013 to August 2018. One-to-five propensity score matching was conducted between patients who received
maoto in addition to a
neuraminidase inhibitor and those who received a
neuraminidase inhibitor alone. Hospitalization within seven days of the
influenza diagnosis was compared in the matched groups using the Mantel-Haenszel test. Results We identified 1.79 million cases of
influenza from the database in the 5-year study period.
Maoto was prescribed for 3.9% of the 1.67 million cases receiving a
neuraminidase inhibitor. In the 64,613 propensity score-matched groups of patients, the 7-day hospitalization rate was 0.116% (n=75) for patients with
maoto and 0.122% (n=394) for patients without
maoto. The difference between these treatment groups was nonsignificant (common odds ratio, 0.95; 95% confidence interval, 0.74 to 1.22; p=0.695). Conclusion The addition of
maoto to a
neuraminidase inhibitor was not associated with a decrease in hospitalization among nonelderly patients with
influenza. Further research is necessary to clarify the indication and efficacy of
maoto.