Outcome reporting in randomized trials for shoulder disorders: literature review to inform the development of a core outcome set

Objectives
To explore the outcome domains and measurement instruments reported across randomized trials of any interventions for various shoulder disorders.

Methods
We searched for shoulder trials included in Cochrane reviews published up to Issue 10, 2015, or indexed in PubMed between 2006 and 2015. Trials were eligible for inclusion if they focused on any intervention for rotator cuff disease, adhesive capsulitis, shoulder instability, glenohumeral or acromioclavicular osteoarthritis, shoulder dislocation, proximal humeral or humeral head fractures, or unspecified shoulder pain. Two authors independently selected trials for inclusion and extracted information on the domains and measurement instruments reported, with consensus discussion among all authors where required.

Results
We included 409 trials, published between 1954 and 2015. Across the trials, we identified 319 different instruments that were classified into 32 domains. Most trials reported a measure of pain (90%), range of motion (78%), and physical function (71%). Measurement of adverse events was reported in only 31% of trials. Muscle strength was reported in 44% of trials and imaging outcomes were reported in 21% of trials. Other patient-reported outcome measures such as global assessment of treatment success, health-related quality of life, work ability, and psychological functioning, were each reported in 15% or fewer trials. Most domains were reported at a similar frequency across different shoulder disorders.

Conclusion
There was wide diversity in the domains and measurement instruments reported. Our results provide the foundation for the development of a core outcome set for use in future trials across all shoulder disorders.