From standard systematic reviews to living systematic reviews.

Systematic reviews (SRs) have become a central tool for evidence-based health care over the last 30 years. The number of SRs being published has increased steadily. However, concerns have been raised regarding the duplication of work, methodological flaws and the currency of many systematic reviews, also in the context of the COVID-19 pandemic. Living systematic reviews (LSRs) offer a new approach to updating systematic reviews, particularly in high-priority research fields that face the challenge of dynamically evolving and sometimes uncertain evidence. Continual updates serve to ensure that LSRs remain current and methodologically rigorous. As a new element of the evidence ecosystem, LSRs can inform living guidelines and recommendations, user-adapted formats, decisions at the patient and system level as well as gaps in primary research.