The method to identify invasive mechanical ventilation with Japanese claim data

Dr. Ohbe et al. reported that only 40.4% of patients who underwent invasive mechanical ventilation were treated in intensive care units, with significant variations in intensive care unit admission rates observed between hospitals and regions using Japanese claims data. The issue of validation when using claim data has been reported in previous studies. The definition of invasive mechanical ventilation used by Dr. Ohbe et al. appears overly broad, encompassing non-invasive mechanical ventilations via nasal mask and manual ventilation. We discuss the limitation of their method in identifying invasive mechanical ventilation, which is critical for defining the study population.