Open-label placebo for non-specific pain in the emergency department (OLP EM): study protocol for a mixed-method randomised control feasibility study in Switzerland.

INTRODUCTION

Non-specific pain (NSP), defined as pain without a clear pathological cause, is a common presentation in the emergency department (ED). There is no universally accepted analgesic strategy, but non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are often prescribed. However, the established efficacy of NSAIDs for NSP is limited. Additionally, NSAIDs are associated with an increased risk of upper gastrointestinal bleeding, acute kidney injury and cardiovascular events, such as myocardial infarction and stroke. There is increasing evidence supporting the analgesic effects of open-label placebo (OLP), defined as placebo administered to patients without deception, in a broad variety of settings. Accordingly, OLP could be a safer, effective analgesic treatment option for NSP. To our knowledge, this is the first study investigating the feasibility of OLP for NSP in the ED. Therefore, our primary objective is to assess whether OLP is a feasible treatment option in this setting.

METHODS AND ANALYSIS

Patients diagnosed with acute NSP will be prospectively recruited at discharge in the ED at the University Hospital of Basel, Switzerland. Patients treated with pain medication for >7 days prior to ED visit or with chronic pain will be excluded. Patients will be randomised to receive either OLP (intervention) or ibuprofen (control). Rescue medication will be ibuprofen in both groups. Daily online self-assessment will take place during the first 7 days after the baseline visit as well as on day 30. A qualitative interview will be conducted on day 30. The primary outcome is feasibility, consisting of acceptability, adherence to the protocol and patient satisfaction. Clinical outcomes will focus on pain intensity and interference according to the Brief Pain Inventory Short Form as well as adverse events.

ETHICS AND DISSEMINATION

The study protocol has received approval from the ethics committee for Northwestern and central Switzerland (EKNZ; project ID 2024-00089). The results will be disseminated in peer-reviewed journals and at scientific conferences.

TRIAL REGISTRATION NUMBER

Swiss National Clinical Trials Portal (SNCTP000005852); Clinicaltrial.gov (NCT06408519).