Scope, Prospects, and Limitations of Living Systematic Reviews in Medical Literature: A Narrative Overview

Living systematic reviews (LSRs) have emerged as a response to the persistent lag between the publication of primary research and its incorporation into systematic reviews, a delay that has historically spanned several years and can render a meaningful proportion of reviews outdated within two years of publication. Since their formal introduction in 2014, LSRs have evolved from a single conceptual proposal into a maturing methodological field, supported by a dedicated PRISMA reporting extension, decision frameworks for determining when a living approach is warranted, and demonstrated applications in COVID-19 therapeutics, vaccine effectiveness, long COVID, and the development of formal clinical guidelines. Uptake accelerated markedly during the COVID-19 pandemic, and automation, ranging from human-machine collaborative workflows to large language models, has become central to sustaining the frequency of updates required by the living model, with reported gains in screening and extraction efficiency. However, methodological guidance for reporting and appraising LSRs remains underdeveloped relative to the pace of adoption, statistical methods for repeated meta-analytic updating are heterogeneous and imperfectly matched to network meta-analyses, and operational surveys consistently document inconsistent update schedules, limited communication of living status, and resource constraints that threaten their long-term sustainability. Realizing the full clinical and policy value of LSRs will require coordinated progress across methodological guidance, automation, and institutional support. Hence, this narrative review aims to examine the above concerns related to LSR.