Diagnostic performance of neck circumference for detecting steatotic liver disease in adults: a systematic review and...

Steatotic liver disease (SLD), particularly its metabolic forms (metabolic dysfunction-associated steatotic liver disease and metabolic dysfunction-associated steatohepatitis), is highly prevalent worldwide yet remains substantially underdiagnosed. Neck circumference (NC) is a simple anthropometric measure reflecting upper-body adiposity and cardiometabolic risk and has been increasingly investigated as a potential screening or risk-stratification tool for SLD. However, existing evidence is heterogeneous, and no comprehensive meta-analysis has synthesised the diagnostic performance of NC for detecting SLD. This systematic review and meta-analysis aim to evaluate the diagnostic accuracy and predictive value of NC in adults and to explore sources of heterogeneity across populations and study characteristics.

A systematic search of PubMed, Scopus, Web of Science and the Cochrane Library will be conducted for English-language studies published between January 2010 and September 2025. Observational studies in adults reporting NC measurements and confirmed steatotic liver disease diagnosed by imaging or biopsy will be included. Two reviewers will independently perform study selection and data extraction. Risk of bias and methodological quality will be assessed using a dual-framework approach: the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool for diagnostic accuracy domains and the Joanna Briggs Institute (JBI) critical appraisal checklists for broader observational study design considerations. The primary outcomes are pooled sensitivity and specificity of neck circumference for detecting steatotic liver disease. Secondary outcomes include ORs, relative risks, correlation coefficients and diagnostic accuracy measures, as well as comparisons with other anthropometric indicators. Random-effects meta-analyses will be conducted where appropriate, with subgroup, sensitivity and publication bias analyses planned. Certainty of evidence for primary diagnostic accuracy outcomes (pooled sensitivity and specificity) and key secondary association outcomes will be assessed using the Grading of Recommendations Assessment, Development and Evaluation framework.

Ethical approval is not required, as this study synthesises published data. Results will be disseminated through peer-reviewed publication and scientific conferences to inform clinicians, researchers and policymakers on the potential role of neck circumference in screening and risk stratification for steatotic liver disease.