An OMERACT Initiative Toward Consensus to Identify and Characterize Candidate Contextual Factors: Report from the Contextual Factors Working Group

Objective. The importance of contextual factors (CF) for appropriate patient-specific care is widely acknowledged. However, evidence in clinical trials on how CF influence outcomes remains sparse. The 2014 Outcome Measures in Rheumatology (OMERACT) Handbook introduced the role of CF in outcome assessment and defined them as "potential confounders and/or effect modifiers of outcomes in randomized controlled trials." Subsequently, the CF Methods Group (CFMG) was formed to develop guidance on how to address CF in clinical trials.

Methods. First, the CFMG conducted an e-mail survey of OMERACT working groups (WG) to analyze how they had addressed CF in outcome measurement so far. The results facilitated an informed discussion at the OMERACT 2016 CFMG Special Interest Group (SIG) session, with the aim of gaining preliminary consensus regarding an operational definition of CF and to make a first selection of potentially relevant CF.

Results. The survey revealed that the WG had mostly used the OMERACT Handbook and/or the International Classification of Functioning, Disability and Health (ICF) definition. However, significant heterogeneity was found in the methods used to identify, refine, and categorize CF candidates. The SIG participants agreed on using the ICF as a framework along with the OMERACT Handbook definition. A list with 28 variables was collected including person-related factors and physical and social environments. Recommendations from the SIG guided the CFMG to formulate 3 preliminary projects on how to identify and analyze CF.

Conclusion. New methods are urgently needed to assist researchers to identify and characterize CF that significantly influence the interpretation of results in clinical trials. The CFMG defined first steps to develop further guidance.