Core outcome set for work participation

The main objective of this thesis is to develop a Core Outcome Set for work participation (COS for Work) that can be used in research internationally for any study which may directly or indirectly impact work participation of people with a health problem.
In part I, a conceptual framework was provided for the development of COS for Work, proposing that outcomes can be placed in four categories: (1) initiating employment, (2) having employment, (3) increasing or maintaining productivity at work, and (4) return to employment. Furthermore, a systematic review was conducted exploring how work participation is currently measured. The review included 269 trials reporting on 435 work participation outcomes. Most measured outcomes (196) were on "absence from work and return-to-work", followed by "at-work productivity loss" (132), followed by outcomes on "employment status" (70), and finally least measured were outcomes on "employability" (30). In addition, a survey amongst researchers showed that the choice for measuring a specific outcome was mostly based on its use in previous similar studies. The process of choosing what to measure is mostly done without involvement of stakeholders such as patient representatives.
Part II describes the results of an international multi-stakeholder Delphi study which determined that the following outcomes are included in the COS for Work: "any type of employment including self-employment", "proportion of workers that return-to-work after being absent because of illness", and "time to return-to-work". In addition, this part describes a systematic review and meta-analysis aimed at determining the best clinimetrically sound way to measure the COS for Work outcomes.