This study included ICWM interventional RCTs of UC published in English or Chinese from the date of inception for each database up to 16 June 2023. We included studies on subjects given the diagnosis of UC defined by clear diagnostic criteria or references, regardless of age, gender, course of disease, and severity. The ICWM intervention is defined as the combination of CM therapies and WM treatments. Specifically, we included a wide range of CM interventions, such as herbal medicines, acupuncture, and moxibustion, while only pharmacological therapy of WM was in the intervention group. There were no limitations in the types of control groups and the assessed outcomes. Repeat publications, non-randomized or non-controlled trials, quasi-randomized controlled trials, non-ICWM interventional trials, study protocols, reviews, observational studies, case reports, abstracts, full-text reports not found, and non-human studies were excluded. Table 1 provides details on the inclusion and exclusion criteria of PCC used in this review. The conduction of this review is referred to the Chapter 11-Scoping Reviews of Joanna Briggs Institute Reviewer's Manual for Evidence Synthesis [17, 18], also with some modifications in terms of format as this review focused on the quality assessment.

A systematic search was conducted on 17 June 2023 for the following databases: MEDLINE < 1946 to 16 June 2023 > , Embase < 1974 to 16 June 2023 > , CENTRAL (Cochrane Central Register of Controlled Trials) < May 2023 > , Web of Science < 1900 to 16 June 2023 > , CINAHL < 1937 to 16 June 2023 > , AMED (Allied and Complementary Medicine Database) < 1985 to May 2023 > , CNKI (China National Knowledge Infrastructure) < 1979 to 16 June 2023 > , Wanfang < 1979 to 16 June 2023 > , VIP (Chinese Science and Technology Periodical Database) < 1989 to 16 June 2023 > , CBM (Chinese Biomedical Literature Database) < 1978 to 16 June 2023 > . The search terms were “ulcerative colitis”, “inflammatory bowel disease”, “randomized controlled trial”, “random”, “Chinese medicine”, “herbal”, and “drug”. The detailed search strategy is presented in Additional file 1: Appendix 1.

Endnote 20 (Clarivate, Philadelphia, PA 19130) was used for de-duplication, title and abstract screening. After de-duplication, four review authors (JLZ, NNW, FL, and PJC) independently screened titles and abstracts of the retrieved records based on the inclusion and exclusion criteria, and another two review authors (JSD and JW) conducted a second check. Full text of potentially relevant papers were reviewed (JLZ, NNW, FL, and PJC) and double-checked (JSD and JW) for further assessment of eligibility. Differences of opinion were settled by consensus.

We developed a data extraction Microsoft Excel form to extract data on general characteristics of included records, including study title, publication year and language, information of corresponding author(s), types of journals, types of study design (e.g., assignment, randomization, blinding, sample size and participating centers), features of interventions, types of participant(s) and control(s), period of treatment and follow-up (if any), as well as the categories of diagnosis criteria, outcome(s) and study conclusions. We piloted the extraction form on a random sample of ten included articles and achieved consistency in data item interpretations. Then, four trained authors (JLZ, FL, NNW, and JSD) independently extracted the data, and another two review authors (XZ and JW) conducted a second check. Disagreements were resolved by discussion.

The reporting quality of included studies was evaluated according to a standard checklist of the CONSORT 2010 statement, of which the checklist of the CONSORT for Abstract was extracted for independent evaluation. For rating the CONSORT items, the assessment rules were referred to the CONSORT 2010 statement (including the CONSORT for Abstract) with its explanation and elaboration document which provides the definitions and rationale for each checklist item and examples of good reporting (e.g., scored as 2 points) [19, 20]. The total score of the CONSORT checklist and CONSORT for the abstract checklist was 72 and 34, respectively.

A specially designed checklist comprised of 27 items related to specific characteristics of ICWM trials (Table 2) was developed by five researchers (XZ, JL, PW, FH, and ZXB) based on an internal discussion. This list focused on the identification of critical issues in the procedure of ICWM design, implementation, and assessment, particularly in the selection rationale, details of therapy combination, and the efficacy assessment. Each item/question was scored in terms of three possibilities: “2” for “fully reported”, “1” for “partially reported”, and “0” for “not reported” or “not applicable”. The total score of the ICWM-specific checklist was 54. For rating the ICWM items, the details of scoring rules are presented in Additional file 1: Appendix 2 which includes the explanations for each question and examples of eligible reporting. The quality assessment was independently conducted by one review author and verified by another review author. A total of four authors (YHW, JSD, NNW, and WTC) participated in the quality assessment. Possible disagreements were resolved with the consultation of the third senior review authors (XZ or ZXB).

As this review is focused on reporting characteristics and quality evaluation, we thereby applied frequency and percentage to present categorical variables, and mean (standard deviation) or median (interquartile range, IQR) to present continuous variables in the section of “Results”. For individual item of reporting quality, the compliance rate was calculated with the number of items acquired “2” based on the total number of included reports, which was further categorized as three levels: excellent compliance (> 90%), good compliance (between 65 and 90%), and poor compliance (< 65%). The total scores of the CONSORT, CONSORT for Abstract, and ICWM-specific checklists of RCTs published before and after 2010 were compared with Student’s t test or Mann–Whitney U test. Statistics analyses were performed using SPSS software (version 28.0). Statistical significance was defined as two-sided P value < 0.05.