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A5O4 | Approaches to Estimate and Present Baseline Risks: Recommendations for Cochrane Review Summary of Findings (SoF) Tables

Abstract text
Background: The ‘Summary of Findings’ (SoF) table is a key tool to present the main findings of Cochrane reviews in a transparent and simple format. The SoF table presents an absolute measure of treatment effect, using a measure of baseline risk to convert relative effect sizes. This is desirable as an absolute measure provides an estimate of how likely an intervention is to work in a specific population, or in an individual patient.

Objectives: We explored the relevant methodological literature, compared and identified strengths and weaknesses of different approaches to estimate baseline risk toward the goals of valid, feasible and understandable presentation of absolute measures of effect.

Methods: Baseline risk estimates for health populations were extracted from randomized controlled trials, prognostic systematic reviews, and individual prognostic studies. The Table presents data sources and estimate measures compared. Simulation modeling was used to assess the potential impact of more or less extreme estimates.

Results: A summary of the methodological literature, results of exploratory analyses and simulation studies have been conducted. These analyses have demonstrated that the best estimate of baseline risk depends on the review question, including the size of the treatment effect, how well the trial control groups represent the population of interest, and the heterogeneity in the baseline risk values. It is appropriate to estimate the baseline risk from the median RCT control group rate in many situations; in some cases estimation of baseline risk from prognostic evidence is more appropriate.

Conclusions: We have developed several resources for reviewers/Review Groups in making decisions about baseline risk estimates including: 1. an algorithm to guide decision-making about appropriate choice for baseline risk estimate, 2. recommendations for identifying baseline risk estimates from prognosis studies, 3. a tool to explore the impact of changes in baseline risk estimates on important absolute treatment effect.
Hayden JA1, Tomlinson G2, Ni A3, Parker R4, Cartwright J4, van Tulder M5, Altman D6
1 Dalhousie University, Canada
2 University Health Network, Canada
3 Canada
4 Capital District Health Authority, Canada
5 EMGO, the Netherlands
6 Oxford, United Kingdom
Presenting author and contact person
Presenting author: 
Jill Hayden
Contact person: 
Jill Hayden (Contact this person)
Date and Location
Oral session A5O4
Friday 21 October 2011 - 12:25 - 12:45