Abstract
Our manuscript is a letter to the article "Factors associated with emergency department length of stay of foreign patients visiting a regional core hospital in Japan." by Aoki et al. published ahead of print in Acute Medicine and Surgery. We believe that the manuscript by Aoki et al. is the first publication to suggest that linguistics play an important role in the outcomes of foreign patients in Japanese medical facilities, and applaud them for their contribution. However, we also believe that further assessments are required to make their implications more robust. Therefore, in our manuscript, we would like to highlight several criteria that should be included in such studies, derived from studies that have been conducted under similar situations in Japanese medical facilities.