Cochrane apparently do have some stakeholders and consumer involvement in their work.The presence of patients in research and guideline evaluation is still largely perceived as a silly thing by most MDs, an attitude that may turn into hostility if it overturns old belief systems. As we all know, knowledge in science is immutable and cannot change. As the present opinion paper basically argues.
NICE has a model that allows it, but recent overtures to work with Cochrane instead, who don't bother with such things and are far more secretive, doesn't suggest too many good things. It's also not the norm to be this open, usually this happens in such secrecy that we only ever find out anything once it's published and face a blank wall to any questions asked.
Stakeholder Involvement in Systematic Reviews: Lessons From Cochrane’s Public Health and Health Systems Network