Do cognitive bias and heuristics influence improvement in knee pain in patients with knee osteoarthritis treated with open label placebo? The CHIPS study - An exploratory study using questionnaire and group concept mapping.

Objective: This study explored if the patient-experience and the affect heuristic influenced improvements in painful symptoms, in response to open label placebo injections in patients with knee OA. It furthermore explored if other cognitive biases or heuristics were involved in the response to open-label placebo.

Method: A mixed method study in a pre-specified knee OA cohort.