Effects of participatory organizational interventions on mental health and work performance: a protocol for systematic review and meta-analysis

Abstract Introduction Participatory organizational interventions to improve psychosocial working conditions are important for a safe and healthy work environment. However, there are few systematic reviews or meta-analyses investigating the effects of these interventions on workers’ mental health and work-related outcomes. We intend to apply the protocol for systematic review and meta-analysis to examine the effect of participatory organizational intervention on mental health and work performance. Methods and analysis The participants, interventions, comparisons, and outcomes (PICO) of the studies in this systematic review and meta-analysis are defined as follows: (P) inclusion of all workers, (I) participatory organizational intervention, (C) treatment as usual or no intervention (including waitlist control), and (O) mental health and work performance. Published studies will be searched using the following electronic databases: PubMed, Embase, PsycINFO, PsycArticles, and Japan Medical Abstracts Society. Studies that (1) include participatory organizational intervention, (2) include participants who were working as of the baseline survey period, (3) assess mental health or work performance outcomes, (4) use a cluster randomized controlled trials design, (5) are published in English or Japanese, and (6) are published in peer-reviewed journals (including advanced online publication) will be included. Study selection and the risk-of-bias assessment will be performed independently by 2 reviewers. A meta-analysis will be performed to statistically synthesize the included studies. Publication bias will be assessed for meta-bias using Egger's test as well as visually on a funnel plot. We will assess heterogeneity by using the Q statistic.


Introduction
3][4] For example, higher subjective social support at work, control over work, skill use, and job variety were associated with greater well-being (greater satisfaction, positive and negative affective balance, or less psychiatric disorder). 5On the other hand, high levels of job demands, conf lict demands, and effort-reward imbalance were associated with less well-being (less satisfaction or high psychiatric disorder). 5,6[9][10] Organizational interventions are "planned actions that primarily directly target working conditions with the aim of promoting and maintaining the highest degree of physical, mental, and social well-being of workers in all occupations." 113][14][15] For instance, the International Organization for Standardization (ISO) 45 003 guideline suggests that the participation of workers is essential for developing, planning, implementing, maintaining, evaluating, and continually improving healthy and safe workplaces and managing psychosocial risk. 15orkers' participation increases their control, sense of fairness, justice, and support; their involvement also helps optimize the intervention's fit to the organizational culture and context; hence, promoting worker participation is a necessary component of organizational intervention. 10Sakuraya et al 11 defined participatory organizational intervention as "workers participate on steps of an intervention, such as action planning, implementing, evaluating, and reviewing the intervention."In such participatory organizational interventions, management consent and support are essential. 10Several previous studies have set and emphasized the step of management participation in this type of intervention. 16,17Furthermore, the process of workers participating in an organizational intervention with the agreement of the management could correspond to organizational justice.For example, in such participatory organizational interventions, the decisionmaking process should not be biased by personal self-interest or preconceptions but should ref lect the views of various stakeholders, which corresponds to the rules of procedural justice (eg, bias suppression and representativeness). 18,19 Also, because workers are treated with respect and care, participatory organizational interventions are also considered to be a state of high interactional justice. 20Therefore, such participatory interventions are important management practices that can enhance organizational justice.
Several cluster randomized controlled trials (cRCTs) revealed the effect of participatory organizational interventions.For mental health outcomes, the participatory organizational intervention has effects on improved minor psychiatric morbidity (General Health Questionnaire) 16 and depersonalization (subscale of burnout). 21For work-related outcomes, psychosocial work environment (eg, co-worker support and well-defined and realistic workplace goal), 22 sickness absence, 23 and job performance 16 were also improved by participatory organizational intervention.Thus, participatory organizational intervention may be promising for enhancing mental health and work-related outcomes.
There are few systematic reviews or meta-analyses that gather evidence from cRCTs on the effects of participatory organizational intervention on workers' mental health and work-related outcomes.In previous systematic reviews, organizational interventions had favorable impacts on mental health (eg, decreased distress or burnout) 7,9 and work-related outcomes (e.g., absenteeism, sickness absence). 7,8However, these reviews included nonparticipatory organizational interventions as well as participatory ones.Another systematic review reported a meta-analysis examining the effect of participatory organizational interventions on stress levels (eg, occupational stress or burnout), albeit with nonsignificant results (standardized mean difference [SMD]: −0.12; 95% CI: −0.30 to 0.05). 24However, this meta-analysis targeted only health care workers and included only 2 studies.Thus, further systematic reviews and meta-analyses are needed to gain a more comprehensive understanding of the effects of this intervention among general workers.
Therefore, the objective of this study is to examine the effect of participatory organizational intervention on mental health and work performance among all workers.This review will treat outcomes related to workers' well-being or productivity.To the best of our knowledge, this will be the first systematic review and metaanalysis conducted specifically to investigate the effect of participatory organizational interventions among workers.Especially, our review will include only cRCTs because a non-cRCT study cannot avoid the inf luence of confounding factors, which cause bias in intervention effect estimates. 25Also, in non-cRCT designs, imbalances in participant selection or in dropouts between intervention and control groups are more likely to occur, considering the group assignment may be inf luenced by a variety of factors, including study participant motivation in each cluster. 25Accordingly, the systematic review and meta-analysis, including only cRCTs, is meaningful for high-quality evidence with a low risk of bias regarding the effects of this intervention.

Study design
This is a systematic review and meta-analysis protocol for cRCT studies, following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis protocols (PRISMA-P) guideline 26 (Appendix 1).The systematic review and meta-analysis will be reported according to the PRISMA 2020 guideline. 27The study protocol was registered at the UMIN registry (registration number: UMIN000049453).

Eligibility criteria
The participants, interventions, comparisons, and outcomes (PICO) of the studies in this systematic review and metaanalysis are defined as follows: (P) inclusion of all workers, (I) participatory organizational intervention, (C) treatment as usual or no intervention (including waitlist control), and (O) mental health and work performance.The definition of participatory organizational intervention is based on an opinion paper by Sakuraya et al 11 from 2023.For mental health outcomes, positive mental health (eg, optimism, satisfaction, positive affect, wellbeing, or work engagement), or mental health conditions (eg, mental disorders, depression, burnout, or stress) will be included.In addition, work performance outcomes, such as work capacity evaluation, effectiveness, or presenteeism, will be included.There will be no exclusion criteria for workers based on their employment status, job type, and shift type.
The inclusion criteria are as follows: 1.Studies that include participatory organizational interventions.
2. Studies that include participants who were working as of the baseline survey period.
3. Studies that assess mental health or work performance outcomes.
4. Studies that use a cRCT design.5. Studies published in English or Japanese.6.Studies published in peer-reviewed journals only (including advanced online publication).

Information source, search strategy, and data management
Published studies will be searched using the following electronic databases: PubMed, Embase, PsycINFO, PsycArticles, and Japan Medical Abstracts Society.The search terms will include keywords or those associated with some MeSH headings related to the PICO of the studies.The search strategy is shown in Appendix 2. All identified studies will be managed within both EndNote-20 Library and Microsoft Excel files.Before screening the studies, M. Iida will remove duplicate entries by using EndNote-20 Library and export the data to the Excel file.

Study selection process
We plan to outsource some of the sifting work to specialist contractors.A total of 15 investigators (M.Iida, A. Sakuraya, K.I., H. Asaoka, E.A., A.I., R.I., M. Iwanaga, H.E., Y.O., Y. Kobayashi, Y. Komase, N.S., K.T., and K.W.), and a specialist contractor representative will independently conduct the screening of studies according to the eligibility criteria created earlier in the sifting phase, and the full text of all eligible studies will be obtained.In the full-text review phase, the full texts will be reviewed using a standardized form for assessing eligibility for this study.When resolution cannot be accomplished, the disagreements will be settled by consensus with discussion among all authors.Corresponding authors will be contacted directly if (1) the publication is unclear and may be related to multiple interpretations, or (2)  the collected data from the publication do not show data relevant to our study analyses.The reasons for excluding studies will be recorded.A f lowchart will be provided to show the entire review process.

Data collection
Data will be extracted independently from the included studies by 15 investigators (M.Iida, A. Sakuraya, K.I., H. Asaoka, E.A., A.I., R.I., M. Iwanaga, H.E., Y.O., Y. Kobayashi, Y. Komase, N.S., K.T., and K.W.) using a standardized data extraction form.All authors will consult and reach an agreement to resolve any disagreements or inconsistencies.Data of the year of publication, the country in which the study was conducted, the length of follow-up, sample size, demographic characteristics of participants, the contents of intervention, condition of the control group, and outcome variables, and results for mental health or work performance outcomes will be extracted.This extraction form will be piloted and adjusted as needed.Means and standard deviations (SDs) of outcomes at baseline and post-intervention surveys, as well as the number of participants at analyses of intervention and control groups, will be collected for the metaanalysis.

Risk of bias in individual studies and assessment of metabias
A total of 15 investigators (M.Iida, A. Sakuraya, K.I., H. Asaoka, E.A., A.I., R.I., M. Iwanaga, H.E., Y.O., Y. Kobayashi, Y. Komase, N.S., K.T., and K.W.) will independently assess the study quality of each selected study using the risk-of-bias assessment tool of the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) system. 28,29The risk-of-bias assessment tool of the GRADE system evaluates a cluster-randomized controlled study based on 6 domains: (1a) bias arising from the randomization process; (1b) bias arising from the timing of identification or recruitment of participants; (2) bias due to deviations from intended interventions; (3) bias due to missing outcome data; (4) bias in measurement of the outcome; and (5) bias in selection of the reported result.Each item will be assessed as a low risk of bias, some concerns, or a high risk of bias.Disputes between the 15 evaluators will be resolved by all authors until a consensus is reached.A summary of findings will be created using the GRADE approach to grade the certainty of evidence.Publication bias will be assessed for meta-bias using Egger's test as well as visually on a funnel plot.

Primary analyses
For the main analyses, the included studies will be statistically synthesized by a meta-analysis to estimate the pooled effects of the participatory organizational interventions on mental health and work performance outcomes, respectively.The continuous outcomes will be synthesized by calculating SMDs and their 95% confidence intervals (CIs).If the included studies use dichotomous and continuous variables, the continuous outcomes will be converted to dichotomous variables based on appropriate cutoff points and synthesized by calculating odds ratios or relative risks and their 95% confidence intervals (CIs).If there is no reasonable cutoff point, we will analyze dichotomous variables and continuous variables separately.If a meta-analysis cannot be conducted because only 2 or fewer studies are eligible and included, the findings will be presented in narrative form.If no heterogeneity is observed (eg, types of interventions or populations), a fixedeffect model will be used, otherwise a random-effects model will be used.We will assess the heterogeneity by using the Q statistic. 30ll the collected data and analyzed results will be deposited by the corresponding author and available upon request by external reviewers.

Subgroup and sensitivity analyses
Subgroup analyses will be conducted to compare the results under specific contents of intervention (eg, all workers participate in every step of the intervention vs not) and outcome (eg, positive mental health/mental health conditions), if enough data to conduct such analyses can be collected.Any differences between subgroups will be reported, and our findings will be explained in light of these differences.For included studies with a GRADE of low risk, a sensitivity analysis will be conducted. 28

Patient and public involvement
This study has no direct patient or public involvement in its design.
The findings and results will be submitted to and published in a scientific peer-reviewed journal.

Strengths and limitations
To our knowledge, this will be the first systematic review and meta-analysis to reveal integrated evidence for the effect of participatory organizational intervention on workers' mental health and work performance.This research will demonstrate how this type of intervention can impact the well-being and productivity of workers.Considering the importance of well-being and productivity at a workplace, the findings of this study will be useful for public and occupational health.Particularly, we will include only cRCT studies in this study.By using cRCTs rather than non-cRCTs we can avoid confounding and selection bias; our systematic review and meta-analysis can examine the effect of participatory organizational intervention with a high level of evidence, which has theoretical significance.
However, this systematic review and meta-analysis study may have some limitations.The generalizability of the findings may be restricted based on the demographic characteristics of the participants included in the selected studies.Furthermore, the selection of databases for this review is based on previous studies, and we are not able to make a comprehensive search.For example, articles in languages other than English or Japanese, and gray literature, such as conference proceedings and unpublished manuscripts, will not be included in this review.