Search Strategy Protocol:
The search will adhere to the Preferred Reporting Items for Systematic Reviews
and Meta-Analyses (PRISMA) guidelines. Scopus, PubMed, and Web of Science will
be selected for their expansive coverage and advanced search capabilities. The
search strategy will utilize both textwords and Medical Subject Headings (MeSH)
terms with Boolean logic operators (AND/OR).
Eligibility Criteria Protocol:
To comply with PRISMA reporting guidelines, a robust theoretical framework will
guide the article selection process. The research question centers on
elucidating the significance of IL-33 levels in individuals with metabolic
disorders, emphasizing obesity and T2D. Eligible study designs encompass
prospective or retrospective cohort studies, case-control studies,
cross-sectional studies, and clinical trials assessing IL-33 levels in
individuals with T2D and/or obesity.
Study Records:
During screening, eligibility, and data extraction, studies will be evaluated
in duplicate by two independent reviewers. Disagreements will be resolved by
involving a third reviewer. Data extraction will be organized in a spreadsheet,
and for studies with unclear data representation, authors will be contacted or
WebPlotDigitalizer will be utilized.
Quality Assessment and Risk of Bias:
Joanna Briggs Institute (JBI) critical appraisal checklists tailored to
specific study designs will be used for the assessment. Checklist responses
will be categorized, and the overall methodical quality will be classified as
high, acceptable, or low.
Statistical Analysis:
The meta package in RStudio will be used for statistical analysis. Mean
differences (MD) will be chosen as the measure of effect, and pooled MD will be
calculated using random-effects models to accommodate potential heterogeneity.
The heterogeneity of studies will be measured using I-square (I2) and Tau
square (Tau2). Forest plots will visually present meta-analytic outcomes.
Sensitivity Analysis Protocol:
Sensitivity analyses, including leave-one-out analyses and fixed-effects model
assessments, will be conducted to evaluate robustness.
Publication Bias:
If possible, publication bias will be assessed through funnel plots and
asymmetry hypothesis tests (Egger's or Begg's).