The STROCSS 2024 guideline: strengthening the reporting of cohort, cross-sectional, and case–control studies in surgery

Abstract

Introduction:

First released in 2017, the STROCSS guidelines have become integral for promoting high-quality reporting of observational research in surgery. However, regular updates are essential to ensure they remain relevant and of value to surgeons. Building on the 2021 updates, the authors have developed the STROCSS 2024 guidelines. This timely revision aims to address residual reporting gaps, assimilate recent advances, and further strengthen observational study quality across all surgical disciplines.

Methods:

A core steering committee compiled proposed changes to update the STROCSS 2021 guidelines based on identified gaps in prior iterations. An expert panel of surgical research leaders then evaluated the proposed changes for inclusion. A Delphi consensus exercise was used. Proposals that scored between 7-9 on a nine-point Likert agreement scale, by ≥70% of Delphi participants, were integrated into the STROCSS 2024 checklist.

Results:

In total, 46 of 56 invited participants (82%) completed the Delphi survey and hence participated in the development of STROCSS 2024. All suggested amendments met the criteria for inclusion, indicating a high level of agreement among the Delphi group. All proposed items were therefore integrated into the final revised checklist.

Conclusion:

The authors present the updated STROCSS 2024 guidelines, which have been developed through expert consensus to further enhance the transparency and reporting quality of observational research in surgery.

Introduction

Highlights

• The STROCSS 2021 guidelines were updated through a Delphi consensus exercise.

• Among the 46 participants, a high level of agreement was noted with all proposed amendments and hence were integrated into the final, revised STROCSS checklist.

• The updated STROCSS 2024 guidelines are presented.

Observational studies, encompassing cohort, case–control, and cross-sectional studies, are widely used within surgical research to investigate associations and risk factors¹. However, poor reporting quality has been a persistent issue^2,3. Consequently, readers critically appraise research less effectively, propagating flawed findings, and ultimately leading to research waste⁴. The systematic implementation of reporting guidelines by journals improves the quality of published research^5–7.

Thus, the Strengthening The Report Of Cohort Studies in Surgery (STROCSS) guidelines were introduced in 2017 and have since been updated in 2019 and 2021^8–10. Despite the original focus on cohort studies, the STROCSS guidelines have been designed to additionally enhance the reporting of case–control and cross-sectional studies, due to similarities in their methodologies. Over the past 6 years, the STROCSS guidelines have been widely adopted with over 3200 citations, illustrating their broad acceptance as the standard for reporting observational research in surgery. However, regular revision is vital. To remain aligned with evolving standards and reflect current best practices, we aimed to update the STROCSS 2021 guidelines. Our objectives were threefold: to elevate reporting quality, address any limitations raised since the preceding update, and incorporate recent advances in reporting standards. The updated STROCSS 2024 guidelines look to optimise the quality and translational impact of observational studies across all surgical disciplines.

Methods

The Delphi methodology used in the development of STROCSS 2017 and its subsequent updates in 2019 and 2021 was applied in the development of the STROCSS 2024 guidelines¹¹.

Generation of proposed revisions

A core steering committee proposed revisions to the STROCSS 2021 checklist. Recommendations were based on newly identified gaps and aimed to enhance specificity, comprehensiveness, and relevance.

Delphi consensus process

The proposed amendments to the STROCSS 2021 guidelines were developed by the steering committee. These changes were integrated into a structured questionnaire that sought to garner consensus from an expert panel, via a Delphi exercise. The panel encompassed research leaders across various surgical specialties.

The Delphi questionnaire was sent to all participants using Google Forms. They were asked to review each of the 45 proposed modifications to STROCSS 2021 and indicate the degree to which they agreed with integrating each amendment into the new guidelines, using a nine-point Likert scale. While a score of 1 on this scale translated to ‘strongly disagree’ with the suggested changes, a score of 9 meant ‘strongly agree’. Consensus for inclusion of an item was predefined as ≥70% of participants scoring an item between 7-9. Items meeting this predetermined threshold were updated in the STROCSS 2024 guidelines. If <70% of participants scored an item between 7-9, the item did not achieve consensus for inclusion and was therefore left unaltered.

Participants

Researchers involved in the development of previous STROCSS updates in 2017, 2019, and 2021 were invited again to participate in the expert panel for STROCSS 2024. Notably, editorial board members from the International Journal of Surgery (IJS) were included. As IJS mandates any observational research submissions to comply with the STROCSS guidelines, involving IJS editors provides key insights. Overall, our panel combined accomplished authors, researchers, journal reviewers, and editorial board members representing a variety of surgical disciplines and countries across Asia, Europe, Australia, Africa, North America, and South America. With multidisciplinary and global insights, we ensured the STROCSS 2024 guidelines remain well-equipped to optimise the reporting quality of observational studies globally.

Results

The Delphi questionnaire was distributed to 56 individuals who agreed to participate in the development of the STROCSS 2024 guidelines. A total of 46 individuals (82%) completed the Delphi survey and therefore contributed to the guideline amendments. Table 1 is a comparison table, between STROCSS 2021 and proposed STROCSS 2024, highlighting the changes suggested. Table 2 summarises the scores given by the survey participants to indicate the extent of their agreement with the proposed modifications to each item of the STROCSS 2021 checklist.

Table 1.

The STROCSS 2021 guidelines and the proposed version of the STROCSS 2024 guidelines.

Comparison of STROCSS 2021 and proposed STROCSS 2024
STROCSS 2021			Proposed STROCSS 2024
Topic	Item	Guideline	Topic	Item	Guideline
Title	1	Title  The word cohort or cross-sectional or case–control is included*  Temporal design of study is stated (e.g. retrospective or prospective)  The focus of the research study is mentioned (e.g. population, setting, disease, exposure/intervention, outcome etc.) *STROCSS 2021 guidelines apply to cohort studies as well as other observational studies (e.g. cross-sectional, case–control etc.)	Title	1	Title  The word ‘cohort’ or ‘cross-sectional’ or ‘case–control’ is included*  Temporal design of the study is stated (e.g. retrospective or prospective)  The focus of the study is clearly stated (e.g. population, setting, disease, exposure/intervention, outcome, etc.) *STROCSS 2024 guidelines apply to all observational studies (e.g. cohort, cross-sectional, case–control, etc.)
				2	Highlights  Include three to five bullet points that summarise the key findings of the study  Provide a brief background to the study, the key results and clinical relevance
			Abstract	3a	Structure Provide a structured abstract that includes the following headings:  1. Background  2. Methods  3. Results  4. Conclusions
Abstract	2a	Introduction - briefly describe:  Background  Scientific rationale for this study  Aims and objectives		3b	Background Briefly describe:  Relevant context  Scientific rationale for this study  Aims and objectives
	2b	Methods - briefly describe:  Type of study design (e.g. cohort, case–control, cross-sectional etc.)  Other key elements of study design (e.g. retro-/prospective, single/multicentred etc.)  Patient populations and/or groups, including control group, if applicable  Exposure/interventions (e.g. type, operators, recipients, timeframes etc.)  Outcome measures - state primary and secondary outcome(s)		3c	Methods Briefly describe:  Type of study design (e.g. cohort, case–control, cross-sectional etc.)  Specification of study design (e.g. retro-/prospective, single/multicentred etc.)  All patient groups involved, including control group, if applicable  Exposure/interventions (e.g. type, operators, recipients, dates and time frames etc.)  Outcome measures - explicitly state primary and secondary outcome(s), where appropriate  Statistical methods of assessment used, where applicable
	2c	Results - briefly describe:  Summary data with qualitative descriptions and statistical relevance, where appropriate		3d	Results Briefly describe:  Summary data  Principal findings with qualitative descriptions  Statistical findings and their significance, where appropriate
	2d	Conclusion - briefly describe:  Key conclusions  Implications for clinical practice  Need for and direction of future research		3e	Conclusion  Describe key conclusions briefly  Refer to implications for clinical practice and public health  Describe the need for and direction of future research  Include a concise statement that encapsulates the significance of the research and its contribution to the field
			Keywords	4	Keywords  Include three to six keywords that identify what is covered in the study (e.g. patient population, diagnosis, or surgical intervention)  Include study type as a keyword (e.g. cohort study, cross-sectional study, case–control study etc.)  Include surgical speciality as one of the keywords  Include study location as one of the keywords
Introduction	3	Introduction - comprehensively describe:  Relevant background and scientific rationale for study, with reference to key literature  Research question and hypotheses, where appropriate  Aims and objectives	Introduction	5a	Introduction By referencing key literature throughout, comprehensively describe:  Relevant background and scientific rationale for study  Aims and objectives  Research question and hypotheses, where appropriate  Potential impact of research on future clinical practice  Economic relevance of study to society
				5b	Guideline citation  At the end of the introduction, refer to the STROCSS 2024 publication by stating: ‘This cohort/cross-sectional/case–control study has been reported in line with the STROCSS guidelines [include citation]’
Methods	4a	Registration  In accordance with the Declaration of Helsinki*, state the research registration number and where it was registered, with a hyperlink to the registry entry (this can be obtained from ResearchRegistry.com, ClinicaTrials.goc, ISRCTN etc.)  All retrospective studies should be registered before submission; it should be stated that the research was retrospectively registered * ‘Every research study involving human subjects must be registered in a publicly accessible database before recruitment of the first subject’	Additional information	12a	Registration  In accordance with the Declaration of Helsinki*, state the unique research registration number and where it was registered, with a hyperlink to the registry entry (this can be obtained from ResearchRegistry.com, ClinicalTrials.gov, ISRCTN etc.)  N.B. All retrospective studies should be registered before submission; it should be stated that the research was retrospectively registered. *‘Every research study involving human subjects must be registered in a publicly accessible database before recruitment of the first subject’
	4b	Ethical approval  Reason(s) why ethical approval was needed  Name of the body giving ethical approval and approval number  Where ethical approval was not necessary, reason(s) are provided		12b	Ethical approval  Whether ethical approval was needed or not, stated explicitly  Reason(s) why ethical approval was/was not needed  Name of the body giving ethical approval and approval number
				12c	Informed consent  State explicitly whether informed consent was obtained, or not.  State reason(s) why informed consent was/was not obtained  State the nature of consent (e.g. verbal, written, digital/virtual)*  The authors must provide evidence of consent, where applicable, and if requested by the journal  Consent should be provided for both the original intervention/procedure and publication of the study *If consent was not provided by the patient, explain why (e.g. death of the patient and consent provided by next of kin). If the patient or family members were untraceable, then document the tracing efforts undertaken
	4c	Protocol  Give details of protocol (a priori or otherwise) including how to access it (e.g. web address, protocol registration number etc.)  If published in a journal, cite and provide full reference		12d	Protocol  Give details of protocol (a priori or otherwise) including how to access it (e.g. web address, DOI etc.)  Give details of protocol registration (e.g. protocol registration number, protocol registry’s name etc.)  If published in a journal, cite and provide a full reference  If applicable, detail any amendments made to the original protocol, giving reasons why the changes were made
	4d	Patient and public involvement in research  Declare any patient and public involvement in research  State the stages of the research process where patients and the public were involved (e.g. patient recruitment, defining research outcomes, dissemination of results etc.) and describe the extent to which they were involved.
	5a	Study design  State the type of study design used (e.g. cohort, cross-sectional, case–control etc.)  Describe other key elements of study design (e.g. retro-/prospective, single/multicentred etc.)	Methods: Study Design	6a	Study design  State the type of study design (e.g. cohort, cross-sectional, case–control etc.)  Describe other key elements of study design (e.g. retro-/prospective, single/multi-centred etc.)  Specify the duration of the study, including start and end dates
	5b	Setting and timeframe of research - comprehensively describe  Geographical location  Nature of institution (e.g. primary/secondary/tertiary care setting, district general hospital/teaching hospital, public/private, low-resource setting etc.)  Dates (e.g. recruitment, exposure, follow-up, data collection etc.)		6b	Setting and timeframe of research Comprehensively describe:  Specific geographical location  Nature of institution (e.g. primary/secondary/tertiary care setting, district general hospital/teaching hospital, public/private, l- ow-resource setting etc.)  Timeline for study, including dates for recruitment, exposure, follow-up, data collection etc.  Any deviations from the initial study design plan or changes to the timeline during the research, with reasons and implications stated
	5c	Study groups  Total number of participants  Number of groups  Detail exposure/intervention allocated to each group  Number of participants in each group		6c	Study groups  Total number of participants  Number of groups  Number of participants in each group  Detail exposure/intervention allocated to each group  Inclusion and exclusion criteria with clear definitions
	5d	Subgroup analysis - comprehensively describe  Planned subgroup analyses  Methods used to examine subgroups and their interactions		6d	Subgroup analysis Comprehensively describe:  How subgroups were defined  Planned subgroup analyses  Methods used to examine subgroups and their interactions
	6a	Participants - comprehensively describe  Inclusion and exclusion criteria with clear definitions  Sources of recruitment (e.g. physician referral, study website, social media, posters etc.)  Length, frequency and methods of follow-up (e.g. mail, telephone etc.)		6e	Follow-up If applicable, comprehensively describe:  Time, length, frequency, location and methods of follow-up (e.g. mail, telephone, with whom etc.)  Any specific long-term surveillance requirements (e.g. imaging surveillance of endovascular aneurysm repair)  Any specific postoperative instructions (e.g. postoperative medications, targeted physiotherapy etc.)
	6b	Recruitment - comprehensively describe  Methods of recruitment to each patient group (e.g. all at once, in batches, continuously till desired sample size is reached etc.)  Any monetary incentivisation of patients for recruitment and retention should be declared; - clarify the nature of any incentives provided  Nature of informed consent (e.g. written, verbal etc.)  Period of recruitment	Methods: Participant Recruitment	7a	Recruitment Comprehensively describe:  Period of recruitment  Methods of recruitment to each patient group (e.g. all at once, in batches, continuously till desired sample size is reached etc.)  Sources of recruitment (e.g. physician referral, study website, social media, posters etc.)  Any monetary/non-monetary incentivisation of participants to encourage involvement should be declared (the nature of any incentives provided must be clarified)  Any challenges encountered during the recruitment processes, including how they were addressed
	6c	Sample size - comprehensively describe  Analysis to determine optimal sample size for study accounting for population/effect size  Power calculations, where appropriate  Margin of error calculation		7b	Sample size Comprehensively describe:  Analysis to determine optimal sample size for study accounting for population/effect size  Power calculations with justifications for chosen statistical power, where appropriate  Margin of error calculation  Any associated ethical considerations
Methods - Intervention and Considerations	7a	Preintervention considerations - comprehensively describe  Preoperative patient optimisation (e.g. weight loss, smoking cessation, glycaemic control etc.)  Preintervention treatment (e.g. medication review, bowel preparation, corrective hypothermia/-volemia/-tension, mitigating bleeding risk, ICU care etc.)	Methods: Intervention and Outcomes	8a	Preintervention considerations Comprehensively describe any preoperative patient optimisation:  Lifestyle optimisation (e.g. weight loss, smoking cessation, glycaemic control etc.)  Medical optimisation (e.g. medication review, treating hypothermia/-volemia/-tension, ICU care etc.)  Procedural optimisation (e.g. nil by mouth, enema etc.)  Other (e.g. psychological support, physiotherapy etc.)
	7b	Intervention - comprehensively describe  Type of intervention and reasoning (e.g. pharmacological, surgical, physiotherapy, psychological etc.)  Aim of intervention (preventative/therapeutic)  Concurrent treatments (e.g. antibiotics, analgesia, antiemetics, VTE prophylaxis etc.)  Manufacturer and model details, where appropriate		8b	Intervention Comprehensively describe:  Type of intervention and reasoning (e.g. pharmacological, surgical, physiotherapy, psychological etc.)  Aim of intervention (e.g. preventative/therapeutic)  Total cost of performing the intervention  Degree of novelty of intervention  Any learning required for intervention  Prevalence or frequency at which the intervention is performed  Concurrent treatments (e.g. antibiotics, analgesia, antiemetics, VTE prophylaxis etc.)  Manufacturer and model details, where appropriate
	7c	Intraintervention considerations - comprehensively describe  Details pertaining to administration of intervention (e.g. anaesthetic, positioning, location, preparation, equipment needed, devices, sutures, operative techniques, operative time etc.)  Details of pharmacological therapies used, including formulation, dosages, routes and durations  Figures and other media are used to illustrate		8c	Intraintervention considerations Using figures and other media to illustrate wherever appropriate, comprehensively describe:  Details pertaining to administration of intervention (e.g. anaesthetic, positioning, location, preparation, equipment needed, devices, sutures, operative techniques, operative time etc.)  For pharmacological therapies, the formulation, dosages, routes, strength and durations  For surgery, any postoperative instruction (e.g. when to remove staples or sutures)  The degree of novelty for a surgical technique/device (e.g. ‘first in human’)
	7d	Operator details - comprehensively describe  Requirement for additional training  Learning curve for technique  Relevant training, specialisation and operator’s experience (e.g. average number of the relevant procedures performed annually)		8d	Operator details Comprehensively describe:  Requirement for additional training  Learning curve for technique, including how it was evaluated (e.g. number of cases required to reach a defined level of proficiency)  Relevant training, specialisation, and operator’s experience (e.g. average number of the relevant procedures performed annually)  Any institutional support that was provided to operators to facilitate their training
				8e	Setting of intervention Comprehensively describe:  Setting in which the intervention was performed  Level of experience the centre has in performing the intervention
	7e	Quality control - comprehensively describe  Measures taken to reduce interoperator variability  Measures taken to ensure consistency in other aspects of intervention delivery  Measures taken to ensure quality in intervention delivery		8f	Quality control Comprehensively describe:  Measures taken to reduce interoperator variability (e.g. regular team meetings, calibration exercises)  Measures taken to ensure consistency in other aspects of intervention delivery (e.g. data collection)  Measures taken to ensure quality in intervention delivery
	7f	Postintervention considerations - comprehensively describe  Postoperative instructions (e.g. avoid heavy lifting) and care  Follow-up measures  Future surveillance requirements (e.g. blood tests, imaging etc.)		8g	Postintervention considerations Comprehensively describe:  Postoperative instructions and care (e.g. avoid heavy lifting, dietary restrictions etc.)  Follow-up measures  Future surveillance requirements (e.g. blood tests, imaging etc.)  How patient engagement with postintervention instructions will be encouraged and monitored  If applicable, the criteria for patient discharge from the medical facility
	8	Outcomes - comprehensively describe  Primary outcomes, including validation, where applicable  Secondary outcomes, where appropriate  Definition of outcomes  If any validated outcome measurement tools are used, give full reference  Follow-up period for outcome assessment, divided by group		8h	Definition of outcomes  Define primary outcomes, including validation with full reference to relevant studies, where applicable  Define secondary outcomes, where appropriate  Describe methods or instruments used to measure each outcome, with full reference given if validated  Describe follow-up period for outcome assessment, divided by group
	9	Statistics - comprehensively describe  Statistical tests and statistical package(s)/software used  Confounders and their control, if known  Analysis approach (e.g. intention to treat/per protocol)  Any subgroup analyses  Level of statistical significance		8i	Statistics Comprehensively describe:  Statistical tests and statistical package(s)/software used  Rationale behind the statistical tests/software of choice  Confounders and their control, if known  Analysis approach (e.g. intention to treat/per protocol)  Any subgroup analyses  Level of statistical significance  How the results of the statistical analyses are presented (e.g. P values, confidence intervals, point estimates etc.)
Results	10a	Participants - comprehensively describe  Flow of participants (recruitment, nonparticipation, cross-over and withdrawal, with reasons). Use figure to illustrate.  Population demographics (e.g. age, sex, relevant socioeconomic features, prognostic features etc.)  Any significant numerical differences should be highlighted	Results	9a	Participants Comprehensively describe:  With reasons, the flow of participants (recruitment, nonparticipation, cross-over and withdrawal), using a figure to illustrate where appropriate  Population demographics (e.g. age, sex, relevant socioeconomic features, prognostic features etc.)  Any significant numerical differences across groups  If applicable, the longitudinal changes in participant flow/demographics over time
	10b	Participant comparison  Include table comparing baseline characteristics of cohort groups  Give differences, with statistical relevance  Describe any group matching, with methods		9b	Participant comparison  Include table comparing baseline characteristics of cohort groups, with statistical data included  Concisely, highlight the principal, significant findings  Describe any group matching, with methods
	10c	Intervention - comprehensively describe  Degree of novelty of intervention  Learning required for interventions  Any changes to interventions, with rationale and diagram, if appropriate
	11a	Outcomes - comprehensively describe  Clinician-assessed and patient-reported outcomes for each group  Relevant photographs and imaging are desirable  Any confounding factors and state which ones are adjusted		9c	Outcomes Comprehensively describe:  Clinician-assessed and patient-reported outcomes (e.g. questionnaires with quality-of-life scales) for each group  Expected versus attained outcomes, as assessed by the clinician*  Primary and secondary outcomes, as previously defined (Item 8h)  Details of when the outcomes were recorded (e.g. at how many months/years postoperatively)  Relevant photographs and imaging are desirable  Any confounding factors and state which ones are adjusted and how  Any changes to interventions, with rationale and diagram, if appropriate  *NB: reference relevant literature to inform expected outcomes
	11b	Tolerance - comprehensively describe  Assessment of tolerability of exposure/intervention  Cross-over with explanation  Loss to follow-up (fraction and percentage), with reasons		9d	Tolerance Comprehensively describe:  Assessment of tolerability of exposure/intervention within patient groups  Methods of measuring tolerance/adherence  If applicable, specific patient perspectives  Whether these results will have an impact on the long-term applicability of the findings in clinical practice  Loss to follow-up (fraction and percentage), with reasons
	11c	Complications - comprehensively describe  Adverse events and classify according to Clavien–Dindo classification*  Timing of adverse events  Mitigation for adverse events (e.g. blood transfusion, wound care, revision surgery etc.) * Dindo D, Demartines N, Clavien P-A. Classification of Surgical Complications. A New Proposal with Evaluation in a Cohort of 6336 Patients and Results of a Survey. Ann Surg. 2002; 240(2): 205-213		9e	Complications Comprehensively describe:  Adverse events, classified according to the Clavien–Dindo classification*  Timing of adverse events  Precautionary measures taken to prevent complications (e.g. antibiotic or venous thromboembolism prophylaxis)  Management of adverse events (e.g. blood transfusion, wound care, revision surgery etc.)  If applicable, whether the complication was reported to the national agency/pharmaceutical company  If applicable, specify whether any complications were discussed locally and the impact of such discussions (e.g. during team morbidity & mortality meetings)  State explicitly if there were no complications/adverse outcomes *Dindo D, Demartines N, Clavien P-A. Classification of Surgical Complications. A New Proposal with Evaluation in a Cohort of 6336 Patients and Results of a Survey. Ann Surg. 2002; 240(2): 205-213
	12	Key results - comprehensively describe  Key results with relevant raw data  Statistical analyses with significance  Include table showing research findings and statistical analyses with significance		9f	Key results Describe:  Key findings, supported by relevant raw data and corresponding statistical analyses with significance
Discussion	13	Discussion - comprehensively describe  Conclusions and rationale  Reference to relevant literature  Implications for clinical practice  Comparison to current gold standard of care  Relevant hypothesis generation	Discussion	10a	Principal findings  By referencing key, relevant literature throughout, comprehensively describe:  Summary of key findings and conclusions  Rationale behind conclusions drawn  Comparison to current gold standard of care, current guidelines or similar research  Implications of findings for future clinical practice and guidelines  Relevant hypothesis generation
	14	Strengths and limitations - comprehensively describe  Strengths of the study  Weaknesses and limitations of the study and potential impact on results and their interpretation  Assessment and management of bias  Deviations from protocol, with reasons		10b	Strengths and limitations Comprehensively describe:  Strengths of the study  Weaknesses and limitations of the study  Measures taken to overcome the limitations, if applicable  Potential impact on results and their interpretation  Assessment and management of bias  Deviations from protocol, with reasons stated
	15	Relevance and implications - comprehensively describe  Relevance of findings and potential implications for clinical practice  Need for and direction of future research		10c	Relevance and implications Comprehensively describe:  Relevance of findings  Potential implications for future clinical practice and guidelines  Measures that can be taken to enhance the quality of research study  Need for and direction of future research
Conclusion	16	Conclusions  Summarise key conclusions  Outline key directions for future research		11	Conclusions  Summarise key conclusions, in a concise manner  Outline scope for and direction of future research
			Additional information	12a-12d	Items 12a-12d of STROCSS 2024 correlate with items 4a-4d of STROCSS 2021.
Declarations	17a	Conflicts of interest  Conflicts of interest, if any, are described	Declarations	13b	Conflicts of interest  Conflicts of interest, if any, are described
	17b	Funding  Sources of funding (e.g. grant details), if any, are clearly stated  Role of funder		13c	Funding  Sources of funding (e.g. grant details), if any, are clearly stated  Role of funder stated  Guarantor named
	17c	Contributorship  Acknowledge patient and public involvement in research; report the extent of involvement of each contributor		13a	Contributorship  Acknowledge any patient and/or public and/or professional involvement in research  Report the extent of involvement of each contributor, specifically stating what they contributed to (e.g. patient recruitment, defining research outcomes, dissemination of results etc.).
				13d	Data sharing statement  Explicitly state whether or not the datasets generated during study are available on request

Table 2.

STROCSS 2024 Delphi scores.

Item	1–3 (n (%))	4–6 (n (%))	7–9 (n (%))
1	1 (2.2)	2 (4.3)	43 (93.5)
2	1 (2.2)	2 (4.3)	43 (93.5)
3a	0 (0.0)	2 (4.3)	44 (95.7)
3b	1 (2.3)	5 (11.4)	38 (86.4)
3c	0 (0.0)	5 (10.9)	41 (89.1)
3d	1 (2.2)	4 (8.7)	41 (89.1)
3e	1 (2.2)	4 (8.7)	41 (89.1)
4	5 (10.9)	4 (8.7)	37 (80.4)
5a	2 (4.3)	3 (6.5)	41 (89.1)
5b	1 (2.2)	0 (0.0)	45 (97.8)
6a	0 (0.0)	3 (6.5)	43 (93.5)
6b	1 (2.2)	6 (13.0)	39 (84.8)
6c	0 (0.0)	1 (2.2)	45 (97.8)
6d	1 (2.2)	3 (6.5)	42 (91.3)
6e	1 (2.2)	3 (6.5)	42 (91.3)
7a	1 (2.2)	3 (6.5)	42 (91.3)
7b	1 (2.2)	2 (4.3)	43 (93.5)
8a	0 (0.0)	9 (19.6)	37 (80.4)
8b	2 (4.3)	3 (6.5)	41 (89.1)
8c	1 (2.2)	4 (8.7)	41 (89.1)
8d	2 (4.3)	5 (10.9)	39 (84.8)
8e	2 (4.3)	1 (2.2)	43 (93.5)
8f	1 (2.2)	7 (15.2)	38 (82.6)
8g	1 (2.2)	3 (6.5)	42 (91.3)
8h	0 (0.0)	1 (2.2)	45 (97.8)
8i	2 (4.3)	2 (4.3)	42 (91.3)
9a	0 (0.0)	6 (13.0)	40 (87.0)
9b	2 (4.3)	5 (10.9)	39 (84.8)
9c	1 (2.2)	4 (8.7)	41 (89.1)
9d	2 (4.3)	3 (6.5)	41 (89.1)
9e	1 (2.2)	2 (4.3)	43 (93.5)
9f	2 (4.3)	3 (6.5)	41 (89.1)
10a	0 (0.0)	2 (4.3)	44 (95.7)
10b	1 (2.2)	4 (8.7)	41 (89.1)
10c	0 (0.0)	3 (6.5)	43 (93.5)
11	2 (4.3)	2 (4.3)	42 (91.3)
12a	2 (4.3)	3 (6.5)	41 (89.1)
12b	2 (4.3)	1 (2.2)	43 (93.5)
12c	1 (2.2)	2 (4.3)	43 (93.5)
12d	1 (2.2)	2 (4.3)	43 (93.5)
13a	1 (2.2)	0 (0.0)	45 (97.8)
13b	1 (2.2)	2 (4.3)	43 (93.5)
13c	1 (2.2)	2 (4.3)	43 (93.5)
13d	0 (0.0)	1 (2.2)	45 (97.8)

Items listed correspond to individual sections of the STROCCS guidelines. The scores given by participants of the Delphi exercise range from 1 (strongly disagree) to 9 (strongly agree).

All 45 proposed changes obtained a score of 7-9 by ≥70% of the participants, indicating consensus with all suggested changes to each item. The complete, revised STROCSS 2024 guidelines are shown in Table 3.

Table 3.

The full, revised STROCSS 2024 checklist.

STROCSS 2024 Guidelines
Topic	Item	Item description	Page number
Title	1	Title  The word ‘cohort’ or ‘cross-sectional’ or ‘case–control’ is included*  Temporal design of the study is stated (e.g. retrospective or prospective)  The focus of the study is clearly stated (e.g. population, setting, disease, exposure/intervention, outcome, etc.) *STROCSS 2024 guidelines apply to all observational studies (e.g. cohort, cross-sectional, case–control, etc.)
Highlights	2	Highlights  Include three to five bullet points that summarise the key findings of the study  Provide a brief background to the study, the key results and clinical relevance
Abstract	3a	Structure  Provide a structured abstract that includes the following headings:  1. Background  2. Methods  3. Results  4. Conclusions
	3b	Background  Briefly describe:  Relevant context  Scientific rationale for this study  Aims and objectives
	3c	Methods Briefly describe:  Type of study design (e.g. cohort, case–control, cross-sectional etc.)  Specification of study design (e.g. retro-/prospective, single/multicentred etc.)  All patient groups involved, including control group, if applicable  Exposure/interventions (e.g. type, operators, recipients, dates and time frames etc.)  Outcome measures - explicitly state primary and secondary outcome(s), where appropriate  Statistical methods of assessment used, where applicable
	3d	Results  Briefly describe:  Summary data  Principal findings with qualitative descriptions  Statistical findings and their significance, where appropriate
	3e	Conclusion  Describe key conclusions briefly  Refer to implications for clinical practice and public health  Describe the need for and direction of future research  Include a concise statement that encapsulates the significance of the research and its contribution to the field
Keywords	4	Keywords  Include three to six keywords that identify what is covered in the study (e.g. patient population, diagnosis, or surgical intervention)  Include study type as a keyword (e.g. cohort study, cross-sectional study, case–control study etc.)  Include surgical speciality as one of the keywords  Include study location as one of the keywords
Introduction	5a	Introduction  By referencing key literature throughout, comprehensively describe:  Relevant background and scientific rationale for study  Aims and objectives  Research question and hypotheses, where appropriate  Potential impact of research on future clinical practice  Economic relevance of study to society
	5b	Guideline citation  At the end of the introduction, refer to the STROCSS 2024 publication by stating: ‘This cohort/cross-sectional/case–control study has been reported in line with the STROCSS guidelines [include citation]’
Methods: Study Design	6a	Study design  State the type of study design (e.g. cohort, cross-sectional, case–control etc.)  Describe other key elements of study design (e.g. retro-/prospective, single/multi-centred etc.)  Specify the duration of the study, including start and end dates
	6b	Setting and timeframe of research Comprehensively describe:  Specific geographical location  Nature of institution (e.g. primary/secondary/tertiary care setting, district general hospital/teaching hospital, public/private, low-resource setting etc.)  Timeline for study, including dates for recruitment, exposure, follow-up, data collection etc.  Any deviations from the initial study design plan or changes to the timeline during the research, with reasons and implications stated
	6c	Study groups  Total number of participants  Number of groups  Number of participants in each group  Detail exposure/intervention allocated to each group  Inclusion and exclusion criteria with clear definitions
	6d	Subgroup analysis Comprehensively describe:  How subgroups were defined  Planned subgroup analyses  Methods used to examine subgroups and their interactions
	6e	Follow-up  If applicable, comprehensively describe:  Time, length, frequency, location and methods of follow-up (e.g. mail, telephone, with whom etc.)  Any specific long-term surveillance requirements (e.g. imaging surveillance of endovascular aneurysm repair)  Any specific postoperative instructions (e.g. postoperative medications, targeted physiotherapy etc.)
Methods: Participant Recruitment	7a	Recruitment Comprehensively describe:  Period of recruitment  Methods of recruitment to each patient group (e.g. all at once, in batches, continuously till desired sample size is reached etc.)  Sources of recruitment (e.g. physician referral, study website, social media, posters etc.)  Any monetary/nonmonetary incentivisation of participants to encourage involvement should be declared (the nature of any incentives provided must be clarified)  Any challenges encountered during the recruitment processes, including how they were addressed
	7b	Sample size Comprehensively describe:  Analysis to determine optimal sample size for study accounting for population/effect size  Power calculations with justifications for chosen statistical power, where appropriate  Margin of error calculation  Any associated ethical considerations
Methods: Intervention and Outcomes	8a	Pre-intervention considerations Comprehensively describe any preoperative patient optimisation:  Lifestyle optimisation (e.g. weight loss, smoking cessation, glycaemic control etc.)  Medical optimisation (e.g. medication review, treating hypothermia/-volemia/-tension, ICU care etc.)  Procedural optimisation (e.g. nil by mouth, enema etc.)  Other (e.g. psychological support, physiotherapy etc.)
	8b	Intervention Comprehensively describe:  Type of intervention and reasoning (e.g. pharmacological, surgical, physiotherapy, psychological etc.)  Aim of intervention (e.g. preventative/therapeutic)  Total cost of performing the intervention  Degree of novelty of intervention  Any learning required for intervention  Prevalence or frequency at which the intervention is performed  Concurrent treatments (e.g. antibiotics, analgesia, antiemetics, VTE prophylaxis etc.)  Manufacturer and model details, where appropriate
	8c	Intraintervention considerations Using figures and other media to illustrate wherever appropriate, comprehensively describe:  Details pertaining to administration of intervention (e.g. anaesthetic, positioning, location, preparation, equipment needed, devices, sutures, operative techniques, operative time etc.)  For pharmacological therapies, the formulation, dosages, routes, strength and durations  For surgery, any postoperative instruction (e.g. when to - remove staples or sutures)  The degree of novelty for a surgical technique/device (e.g. ‘first in human’)
	8d	Operator details Comprehensively describe:  Requirement for additional training  Learning curve for technique, including how it was evaluated (e.g. number of cases required to reach a defined level of proficiency)  Relevant training, specialisation, and operator’s experience (e.g. average number of the relevant procedures performed annually)  Any institutional support that was provided to operators to facilitate their training
	8e	Setting of intervention Comprehensively describe:  Setting in which the intervention was performed  Level of experience the centre has in performing the intervention
	8f	Quality control Comprehensively describe:  Measures taken to reduce interoperator variability (e.g. regular team meetings, calibration exercises)  Measures taken to ensure consistency in other aspects of intervention delivery (e.g. data collection)  Measures taken to ensure quality in intervention delivery
	8g	Postintervention considerations  Comprehensively describe:  Postoperative instructions and care (e.g. avoid heavy lifting, dietary restrictions etc.)  Follow-up measures  Future surveillance requirements (e.g. blood tests, imaging etc.)  How patient engagement with postintervention instructions will be encouraged and monitored  If applicable, the criteria for patient discharge from the medical facility
	8h	Definition of outcomes  Define primary outcomes, including validation with full reference to relevant studies, where applicable  Define secondary outcomes, where appropriate  Describe methods or instruments used to measure each outcome, with full reference given if validated  Describe follow-up period for outcome assessment, divided by group
	8i	Statistics Comprehensively describe:  Statistical tests and statistical package(s)/software used  Rationale behind the statistical tests/software of choice  Confounders and their control, if known  Analysis approach (e.g. intention to treat/per protocol)  Any subgroup analyses  Level of statistical significance  How the results of the statistical analyses are presented (e.g. P values, confidence intervals, point estimates etc.)
Results	9a	Participants Comprehensively describe:  With reasons, the flow of participants (recruitment, nonparticipation, cross-over and withdrawal), using a figure to illustrate where appropriate  Population demographics (e.g. age, gender, relevant socioeconomic features, prognostic features etc.)  Any significant numerical differences across groups  If applicable, the longitudinal changes in participant flow/demographics over time
	9b	Participant comparison  Include table comparing baseline characteristics of cohort groups, with statistical data included  Concisely, highlight the principal, significant findings  Describe any group matching, with methods
	9c	Outcomes Comprehensively describe:  Clinician-assessed and patient-reported outcomes (e.g. questionnaires with quality-of-life scales) for each group  Expected versus attained outcomes, as assessed by the clinician*  Primary and secondary outcomes, as previously defined (Item 8h)  Details of when the outcomes were recorded (e.g. at how many months/years postoperatively)  Relevant photographs and imaging are desirable  Any confounding factors and state which ones are adjusted and how  Any changes to interventions, with rationale and diagram, if appropriate *NB: reference relevant literature to inform expected outcomes
	9d	Tolerance  Comprehensively describe:  Assessment of tolerability of exposure/intervention within patient groups  Methods of measuring tolerance/adherence  If applicable, specific patient perspectives  Whether these results will have an impact on the long-term applicability of the findings in clinical practice  Loss to follow-up (fraction and percentage), with reasons
	9e	Complications Comprehensively describe:  Adverse events, classified according to the Clavien–Dindo classification*  Timing of adverse events  Precautionary measures taken to prevent complications (e.g. antibiotic or venous thromboembolism prophylaxis)  Management of adverse events (e.g. blood transfusion, - wound care, revision surgery etc.)  If applicable, whether the complication was reported to the national agency/pharmaceutical company  If applicable, specify whether any complications were discussed locally and the impact of such discussions (e.g. during team morbidity & mortality meetings)  State explicitly if there were no complications/adverse outcomes *Dindo D, Demartines N, Clavien P-A. Classification of Surgical Complications. A New Proposal with Evaluation in a Cohort of 6336 Patients and Results of a Survey. Ann Surg. 2002; 240(2): 205-213
	9f	Key results Describe:  Key findings, supported by relevant raw data and corresponding statistical analyses with significance
Discussion	10a	Principal findings By referencing key, relevant literature throughout, comprehensively describe:  Summary of key findings and conclusions  Rationale behind conclusions drawn  Comparison to current gold standard of care, current guidelines or similar research  Implications of findings for future clinical practice and guidelines  Relevant hypothesis generation
	10b	Strengths and limitations Comprehensively describe:  Strengths of the study  Weaknesses and limitations of the study  Measures taken to overcome the limitations, if applicable  Potential impact on results and their interpretation  Assessment and management of bias  Deviations from protocol, with reasons stated
	10c	Relevance and implications Comprehensively describe:  Relevance of findings  Potential implications for future clinical practice and guidelines  Measures that can be taken to enhance the quality of research study  Need for and direction of future research
Conclusion	11	Conclusions  Summarise key conclusions, in a concise manner  Outline scope for and direction of future research
Additional information	12a	Registration  In accordance with the Declaration of Helsinki*, state the unique research registration number and where it was registered, with a hyperlink to the registry entry (this can be obtained from ResearchRegistry.com, ClinicalTrials.gov, ISRCTN etc.)  N.B. All retrospective studies should be registered before submission; it should be stated that the research was retrospectively registered. *‘Every research study involving human subjects must be registered in a publicly accessible database before recruitment of the first subject’
	12b	Ethical approval  Whether ethical approval was needed or not, stated explicitly  Reason(s) why ethical approval was/was not needed  Name of the body giving ethical approval and approval number
	12c	Informed consent  State explicitly whether informed consent was obtained, or not.  State reason(s) why informed consent was/was not obtained  State the nature of consent (e.g. verbal, written, digital/virtual)*  The authors must provide evidence of consent, where applicable, and if requested by the journal  Consent should be provided for both the original intervention/procedure and publication of the study *If consent was not provided by the patient, explain why (e.g. death of the patient and consent provided by next of kin). If the patient or family members were untraceable, then document the tracing efforts undertaken
	12d	Protocol  Give details of protocol (a priori or otherwise) including how to access it (e.g. web address, DOI etc.)  Give details of protocol registration (e.g. protocol registration number, protocol registry’s name etc.)  If published in a journal, cite and provide a full reference  If applicable, detail any amendments made to the original protocol, giving reasons why the changes were made
Declarations	13a	Contributorship  Acknowledge any patient and/or public and/or professional involvement in research  Report the extent of involvement of each contributor, specifically stating what they contributed to (e.g. patient recruitment, defining research outcomes, dissemination of results etc.).
	13b	Conflicts of interest  Conflicts of interest, if any, are described
	13c	Funding  Sources of funding (e.g. grant details), if any, are clearly stated  Role of funder stated  Guarantor named
	13d	Data sharing statement  Explicitly state whether or not the datasets generated during study are available on request

Discussion

Since the inception of the STROCSS guidelines in 2017, they have amassed over 3200 citations. This is a testament to their great acceptance within the surgical research community. We now present the updated STROCSS 2024 guidelines: a standardised framework for observational research reporting in surgery.

Past studies have demonstrated that most surgical journals still do not implement rigorous reporting checks or guidelines for authors². However, analysis has indicated that adherence to comprehensive reporting guidelines leads to significant improvements in manuscript quality and reporting completeness^5,6. As such, we strongly encourage authors, editors, and journals across surgical disciplines to broadly adopt the updated STROCSS 2024 guidelines.

Furthermore, we strongly advise authors to explicitly state their use of and reference the STROCSS 2024 guidelines in their introduction section. They should also submit a completed STROCSS checklist together with their manuscript to assist editors when evaluating alignment with the guidelines during the submission review process. Table 3 constitutes the full and revised STROCSS guidelines, together with a column in which the author can state the page number on which the criterion was met in their submission.

The STROCSS website (https://www.strocssguideline.com/) has made the 2024 checklist available across various formats to promote accessibility and facilitate adoption. We must emphasise that these guidelines represent the minimum detail that should be reported: if something was not done, it should be stated, to aid transparency.

Collective and systematic uptake of STROCSS 2024 by authors, reviewers, editors, and publishers promises to elevate the calibre, translational value, and clinical applicability of observational research in surgery.

Conclusion

We present the updated STROCSS 2024 guidelines. Adoption within the surgical research community of authors, reviewers, editors, and medical journals is strongly encouraged. We urge surgical research stakeholders globally to implement these guidelines when conducting, evaluating, and disseminating observational findings, driving continual improvements in evidence-based patient care.

Through the Delphi consensus exercise and the integration of recent advances in reporting standards, the STROCSS 2024 guidelines were systematically developed to uphold the highest standards for reporting observational research in surgery.

Ethical approval

Not applicable. No patients were involved in the production of these surgical guidelines.

Consent

Not applicable. No patients were involved in the production of these surgical guidelines.

Sources of funding

None.

Author contribution

R.A.A.: concept and design, data interpretation and analysis, drafting, revision and approval of final manuscript; R.R., C.S., A.K., T.F., G.M., and M.N.: design, data collection, data interpretation and analysis, drafting, revision, and approval of final manuscript.

Conflicts of interest disclosure

None declared. The authors have no financial, consultative, institutional, or any other relationships that might lead to bias or conflict of interest.

Research registration unique identifying number (UIN)

1. Name of the registry: not applicable.

2. Unique identifying number or registration ID: not applicable.

3. Hyperlink to your specific registration (must be publicly accessible and will be checked): not applicable.

Guarantor

Riaz A. Agha. E-mail: riaz@ijspg.com

Data availability statement

The data in this guideline is derived from individual responses to the survey and is therefore confidential and not in the public domain.

Provenance and peer review

Not commissioned, internally reviewed.

Collaborators

[1] Salvatore Giordano, Turku University Hospital/University of Turku, Finland. [2] Rolf Wynn, UIT The Arctic University of Norway, Norway. [3] Juan Gómez Rivas, Hospital Clinico San Carlos, Spain. [4] Todd Galvin Manning, Bendigo Health, Australia. [5] Shahzad G. Raja, Harefield Hospital, United Kingdom. [6] Indraneil Mukherjee, Staten Island University Hospital/Northwell, United States. [7] Veeru Kasivisvanathan, University College London, United Kingdom. [8] C S Pramesh, Tata Memorial Centre/Homi Bhabha National Institute, India. [9] Mushtaq Chalkoo, Govt. Medical College Srinagar Kashmir, India. [10] Mohammed Bashashati, Dell Medical School/The University of Texas Austin, United States. [11] Salim Surani, Texas A&M University, United States. [12] Prathamesh Pai, Punyashlok Ahilyadevi Holkar Head & Neck Cancer Institute of India, India. [13] Burcin Ekser, Indiana University School of Medicine, United States. [14] Benjamin J Challacombe, Guy’s and St Thomas’ Hospitals and KCL, United Kingdom. [15] Huseyin Kadioglu, Yeniyüzyil University Department of General Surgery, Türkiye. [16] Mangesh A Thorat, 1. Queen Mary University of London, London, United Kingdom 2. Guy’s and St Thomas’ NHS Foundation Trust, United Kingdom 3. Faculty of Life Sciences & Medicine, King’s College London. [17] Joerg Albrecht, Cook County Health, United States. [18] Kandiah Raveendran, Fatimah Hospital, Malaysi. [19] Iain Nixon, University of Edinburgh, United Kingdom. [20] Patrick James Bradley, Nottingham University Hospitals, Nottingham, United Kingdom. [21] Alessandro Coppola, Department of Surgery, Sapienza University of Rome, Italy. [22] Oliver J Muensterer, Dr. von Hauner Children’s Hospital, LMU Munich, Germany. [23] Zubing Mei, Shuguang Hospital/Shanghai University of Traditional Chinese Medicine, China. [24] Roberto Coppola, Fondazione Campus Bio Medico, Italy. [25] Ashraf Noureldin, Almana Hospital Khobar, Saudi Arabia. [26] James Ngu, Changi General Hospital, Singapore. [27] Somprakas Basu, All India Institute of Medical Sciences, Rishikesh, India. [28] Teo Nan Zun, Changi General Hospital, Singapore. [29] Andrew J Beamish, Swansea University Medical School, United Kingdom. [30] Michele Valmasoni, University of Padova, Italy. [31] Diana Miguel, Champalimaud Foundation Clinical Centre, Portugal. [32] Duilio Pagano, IRCCS ISMETT UPMC Italy, Italy. [33] M Hammad Ather, Aga Khan University, Pakistan. [34] Ashwini Rao, Manipal Academy of Higher Education, Manipal, India. [35] James Anthony McCaul, Queen Elizabeth University Hospital, Glasgow, Scotland, UK, United Kingdom. [36] Prabudh Goel, All India Institute of Medical Sciences, New Delhi, India. [37] Richard David Rosin, University of the West Indies, Barbados, Barbados. [38] Samuele Massarut, Centro di Riferimento Oncologico di Aviano IRCCS Italy, Italy. [39] Priya Shinde, Homerton Hospital, United Kingdom. [40] Syed Ather Enam, Aga Khan University, Pakistan. [41] Raafat Yahia Afifi Mohamed, Cairo University, Egypt. [42] Priyadarshan Anand Jategaonkar, 1. Jawaharlal Nehru Medical College 2. Acharya Vinoba Bhave Rural Hospital, Maharashtra, India. [43] Achilles Thoma, McMaster University, Canada. [44] Baskaran Vasudevan, MIOT Hospital, Chennai, India. [45] Roberto Klappenbach, Hospital Bicentenario de Esteban Echeverria, Argentina. [46] Gaurav Roy, Sir Ganga Ram Hospital, India.