Meta-analysis of pain and function placebo responses in pharmacological osteoarthritis trials.

Function measures both subjective and objective had less contextual effects than pain measures in OA trials. Our results support the OMERACT-OARSI recommendations to include measures of physical function in all clinical trials of hip and knee OA and suggest that a greater use of function measures might enhance the success rates of pharmacological OA trials. Increasing the availability of mobile health apps should facilitate the acquisition of measured function data.