I read the research article on the assessment of gastric volume in fasting patients with or without diabetes and the accompanying editorial with profound interest. I congratulate Perlas et al. for this path-breaking study and greatly value the editorial providing further insights on this interesting topic. I wish to present my reflections specifically on the design of the study.

The noninferiority trial is typically performed to assess whether a new treatment can offer improved safety or rather fewer unwanted effects, convenience, or reduced cost when compared to an established treatment.  However, the current study only assessed the impact of fasting in two different populations (persons with or without diabetes) and no intervention was performed.  Furthermore, the statistical analysis should compare the CI’s distribution with a designated noninferiority margin (delta), and null effect preferably with a diagram depicting all of them. More particularly, the planning focusing on these points should happen during the design stage itself. Perlas et al. did not mention these points in the trial registration. Indeed, they stated the type of study as an “Observational” one. Notably, the statement “This study follows the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines” reinforces that the type of this study is only “observational” and it is hard to fit it with a “noninferiority study.”