Review for 10.1186/s12876-023-02767-7 (2023)

Title: Development of a scoring model based on objective factors to predict gangrenous/
perforated appendicitis
Version: 2 Date: 29 Mar 2023
Reviewer:  Jun Fujishiro
Reviewer's report:
In this revision, most of the major critiques by the editor and the reviewers are appropriately
explained in the response letter. However, my concern is the performance of the model in the
study. While the feature of the study is developing a model based on objective factors, the
performance was not superior to previously reported models. The value of the study seems to
be limiting for me.
Another concern is that most of these explanations in the response letter are not included in
the revised manuscript. The manuscript would be improved if these explanations be reflected in
the revised manuscript. Especially, the followings contents in the response letter are important
issues;
1) Validation using 2022 data at their hospital (In response to the Editor's comment). This
validation data would improve the study.
"First, the cases are not so much in fact, the authors should use an external dataset from other
hospitals, from open database, or even patients from other study periods such as year 2022 or
year 2013 for confirmation of the study result.
#We applied our scoring model to eligible patients who underwent emergency surgery in 2022
at our hospital, and the area under the receiver operating characteristic curve was 0.782 (95%CI:
0.511-1.000), similar to the present study."
2) The comparison of the developed model with previously reported ones (In response to the
Reviewer 2). This should be included in the Discussion.
"The performance of the model developed in the study was not compared with that of the
previously reported models for the discrimination of GPA or complicated appendicitis. The
value of the model or the study will be evaluated with the comparison.
#We thank the reviewer for this pertinent comment. We examined two scoring models
(including CT findings) from previous studies(*1,2) for the cases in our study. A receiver
operating characteristic curve analysis was performed, and our scoring model was comparable
to the other scoring models (see below).
*1. Imaoka Y, Itamoto T, Takakura Y, Suzuki T, Ikeda S, Urushihara T. Validity of predictive
factors of acute complicated appendicitis. World J Emerg Surg. 2016;11:48.
*2. Atema JJ, van Rossem CC, Leeuwenburgh MM, Stoker J, Boermeester MA. Scoring system
to distinguish uncomplicated from complicated acute appendicitis. Br J Surg. 2015;102:979-90.
(Figure comparing ROC curve of their model and previously reported models. )"
3) Basic clinical practice for acute appendicitis at their institution (In response to Reviewer 2).
The readership would understand the background of the study if basic clinical practice at their
institution were provided in the Materials and Methods or Discussion.
"Basic clinical practice for acute appendicitis at their institution such as an indication of CT scan
and selection criteria for the treatment (emergency surgery or non-operative
management). These may influence the model in this study. There are apparently more GPA
patients (56.3%) than that is expected in the real world.
#We thank the reviewer for the important comment. In our department, there are no
established criteria for treatment selection, rather it is largely at the discretion of the attending
physician. In recent years, however, appendicitis with mild inflammation is often treated
nonoperatively, and we consider that this is the reason why many patients have GPA. In the
future, this model can be used to aid in treatment selection."