Extreme Heterogeneity Reported in Published Anatomical Meta-Analyses: A Meta-Epidemiological Study

Area of Science:

• Anatomy
• Biostatistics
• Medical Research Methodology

Background:

• Meta-analytic methodology is increasingly used in anatomical research.
• High statistical heterogeneity is common in anatomical meta-analyses but often under-discussed.
• Understanding heterogeneity is crucial for accurate anatomical evidence synthesis.

Purpose of the Study:

• To investigate the prevalence and patterns of statistical heterogeneity in anatomical meta-analyses.
• To explore the implications of this heterogeneity for interpreting anatomical evidence.
• To assess the current state of heterogeneity reporting in the field.

Main Methods:

• A systematic PubMed search was conducted for anatomical meta-analyses published up to May 21, 2026.
• Studies focused on human structural anatomy were included.
• Reported I² values were extracted and descriptively analyzed across anatomical categories.

Main Results:

• 61 anatomical meta-analyses with analyzable data were included.
• The mean reported I² value was 95.27%, with 86.9% of studies exceeding 90%.
• Consistently high heterogeneity was observed across skeletal, peripheral nerve, and vascular anatomy.

Conclusions:

• Extreme statistical heterogeneity is a pervasive characteristic of anatomical meta-analyses.
• This variability likely reflects genuine biological and methodological differences.
• Pooled anatomical estimates, especially those with narrow confidence intervals, demand cautious interpretation due to high interstudy inconsistency.