The mismatch between PRISMA and AMSTAR-2: Does adherence to one standard set authors up to fail another?

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement and AMSTAR-2 are widely used to support the reporting and methodological appraisal of systematic reviews, respectively. Although conceptually complementary, the frameworks are not fully aligned. Consequently, reviews that adhere closely to PRISMA 2020 may receive low AMSTAR-2 confidence ratings. Five recent PRISMA-compliant meta-analyses published in European Radiology illustrate this disconnect: all were rated as having "low" AMSTAR-2 confidence as they failed to provide a detailed list and justification of excluded studies and to report the funding sources of included studies, requirements emphasised by AMSTAR-2 but not formulated as equivalent standalone requirements in PRISMA 2020. Similar patterns have been reported in other clinical fields, suggesting structural misalignment rather than uniformly poor methodological quality. The discrepancy is amplified by AMSTAR-2's designation of critical domains, whereby a single unmet critical item can substantially lower the overall confidence rating, as well as by ambiguity in interpreting certain criteria. Although AMSTAR-2 was intended to support contextual methodological appraisal rather than simple scoring, it is frequently applied as a rigid checklist. Better alignment could include more graduated AMSTAR-2 judgements, clearer appraisal guidance, and incorporation into PRISMA of selected methodological elements emphasised by AMSTAR-2. Ultimately, journals, reviewers, and authors should distinguish reporting completeness from methodological quality and apply both frameworks thoughtfully, transparently, and with appropriate contextual judgement. KEY POINTS: Question Why can PRISMA 2020-compliant systematic reviews receive low AMSTAR-2 confidence ratings? Findings There is structural misalignment between AMSTAR-2 and PRISMA 2020 requirements, and failure to meet a single critical item in AMSTAR-2 can substantially lower the overall rating. Clinical relevance Better alignment between the frameworks and more context-sensitive appraisal are needed to avoid misleading assessments of systematic reviews.