Living Systematic Reviews and Living Guidelines to Maintain the Currency of Public Health Guidelines

Three key criteria are required to be met before an LSR is initiated: (1) the review question is a priority for decision making, (2) certainty in the existing evidence is low or very low, and (3) there is likely to be new research evidence.7 The feasibility ofthe LSR approach to updating evidence has been demonstrated in a number of case studies, including a mixed-methods evaluation that highlighted its potential for reducing time and resource requirements.8 The feasibility of LSRs is also evidenced by their wide-scale adoption in a relatively short period of time. Similar to LSRs, criteria to consider whether a living guideline process is appropriate include the following: (1) the recommendation is a priority for decision making (e.g., areas of known variation in practice), (2) there is a reasonable chance that the existing recommendations will change with the emergence of new evidence, and (3) there is likely to be new research evidence emerging.10 Dozens of living guidelines are currently in production, with a number focused on public health priority areas, including COVID-19.· 1 2 3 4 5 6 V15 A framework for developing living practice guidelines in health care,16 a handbook for developing living guidelines,9 and a series of papers have recently been published to support best practice living guideline methods.17-21 GUIDELINE DEVELOPMENT PROCESS Although living guideline steps are broadly similar to traditional approaches to guideline production, the more frequent generation of research evidence and subsequent guideline updates necessitates some modification to traditional approaches to enable rapid production. Study Designs and Outcomes Although LSRs synthesizing research of any study design can underpin living guidelines, most to date have been applied to clinical care and treatment interventions, for which randomized controlled trials and outcomes amenable to synthesis via meta-analysis are standard. Many public health interventions and policies (e.g., COVID-19 mask mandates, infection control measures) are not as amenable to randomized designs. [...]evidence from nonrandomized studies, including opportunistic studies in which interventions may already have been implemented as part of standard care, may be required to form guideline recommendations.