Details

Autor(en) / Beteiligte

• Hilton Boon, Michele
• Burns, Jacob
• Craig, Peter
• Griebler, Ursula
• Heise, Thomas L
• Vittal Katikireddi, S
• Rehfuess, Eva
• Shepperd, Sasha
• Thomson, Hilary
• Bero, Lisa

Titel

Value and Challenges of Using Observational Studies in Systematic Reviews of Public Health Interventions

Ist Teil von

• American journal of public health (1971), 2022-04, Vol.112 (4), p.548-552

Ort / Verlag

United States: American Public Health Association

Erscheinungsjahr

2022

Link zum Volltext

Quelle

PAIS Index

Beschreibungen/Notizen

• Recent developments in systematic review methods provide opportunities to draw more robust conclusions from observational studies of interventions and increase the public health relevance of reviews. Cochrane public health and health systems reviews have expanded in scope and methods, supported by new chapters on nonrandomized studies in the updated Cochrane Handbook (2021)1 and the development of new, related guidance by the Cochrane Methods Executive. We illustrate these changes while also summarizing the most recent guidance and research on deciding when to include observational studies, identifying and selecting studies, extracting and synthesizing data, assessing risk of bias, and grading certainty of evidence.These developments are particularly important for systematic reviews in public health, in which randomized trials to assess health outcomes are often unfeasible, for example, in the case of large and irreversible infrastructure interventions; unethical, for example, where the primary aim of the intervention is to prevent certain harm; unavailable when decisions are urgently required; or unable to detect harms at the population level, for example, observational pharmacovigilance studies that use adverse event data sets to detect harms after a drug is already on the market and in widespread use. We draw on our experience as editors and authors of Cochrane public health and health systems reviews and as methodologists, supplemented by a hand search of the past five years of key methodology journals. Observational studies of exposures (e.g., environmental exposures) also constitute an important area of current methodological development but are outside the scope of this editorial.Including observational studies in systematic reviews of interventions produces challenges at every stage of designing and conducting a review, beginning with the terminology used to define and identify these studies. Despite efforts to encourage classification according to study design elements rather than labels,2 agreement on terminology is elusive. By "observational studies of interventions," we intend to encompass the range of classifications that may be encountered when considering quantitative evidence of intervention effects other than from randomized trials. These terms include (but are not limited to) nonrandomized studies of interventions,1 quasiexperiments,3 natural experiments,4 and the many specific study design labels that fall within these categories.It is important to note that many of these terms have overlapping meanings and are applied in diverse and inconsistent ways, both in primary research and in systematic reviews. However, for the full value of observational studies of interventions to be realized, it is essential that systematic reviewers look beyond traditional study designs, such as cohort and case-control, and consider the relevance of quasi-experimental designs that can adjust for unobserved confounding, or selection on unobservables.5 At the same time, systematic reviewers must recognize that observational studies are not all of equal evidentiary value, requiring careful assessment of risk of bias, and that their inclusion may increase the resource requirements of a review.