Keeping it Simple Study (KISS)

Introduction: Between 20% and 33% of people across the globe live with a painful musculoskeletal (MSK) condition. Costs correspond to almost 2% of the gross domestic products of European countries, posing a challenge for health care systems across the world. Patients with chronic musculoskeletal pain have a high use of healthcare, reduced work ability, loss of productivity, and loss of quality of life. Current care guidelines underline that pain science education (PSE) is a vital part of the care delivered to people suffering from chronic pain. PSE is thought in part to attenuate central sensitization and improve self-efficacy potentially mediated through decreased pain catastrophizing and modulating nocebo-related effects. On a patient level, PSE has been shown to reduce pain catastrophizing, pain intensity, and fear-avoidance in addition to improved physical functioning, self-efficacy, and pain knowledge. Combining exercise and PSE shows greater short-term improvements in pain, disability, kinesiophobia, and pain catastrophizing compared to exercise alone and the RESTORE-trial showed the benefit of adding cognitive components. On a societal level, PSE has further shown to minimize health expenses. However, some of the proposed barriers include training of the therapist delivering the education, access to training material, time during consultation, and patients' health literacy levels. Even in Denmark, a country with a highly educated population, the prevalence of people with inadequate health literacy is high, with nearly 4 out of 10 people facing difficulties accessing, understanding, appraising, and applying health information. This underlines the need to consider novel ways of delivering PSE across all levels of health literacy.

Due to the lack of tools to facilitate PSE programs, the investigators adapted an existing pain science education program that was developed by Pas et al. (2018) (PNE4Kids) to teach children with chronic pain about the underlying biopsychosocial mechanisms contributing to pain. The adapted version, named PNE4Adults, consists of a manual for the therapist and a board game to enhance engagement and participant involvement. It provides the therapist with a clear "how-to" manual and an accessible way for patients to understand the complex concept of pain. This new PSE program may also hold promise for adult patients with low levels of health literacy and enhance learning due to its practical tools and build-in teach-back. The focus on integrating PSE into rehabilitation may enhance the therapeutic alliance needed to facilitate the patients' ability to manage their own symptoms. The investigators feasibility study in adult patients with chronic MSK pain in community-based rehabilitation (Eiger, Rathleff et al. 2024 - under review) showed that PNE4Adults was well accepted (100%) and understandable by all (100%) patients, including those with low levels of health literacy. Qualitive interviews revealed that patients (irrespective of their health literacy) acquired a deeper understanding of their own situation and their pain. This novel approach may reduce the inequality in delivering of pain education.

Purpose of Sub-project 1 The primary aim of the KISS-project is to evaluate the added effect of PSE ('PNE4Adults') to "usual care" compared to "usual care" alone in community-based rehabilitation.

The investigators hypothesis is PSE plus "usual care" will result in a larger improvement of musculoskeletal health (MSK-HQ) after 3 months (primary endpoint) compared to patients undergoing "usual care" in the municipality.

Purpose of Sub-project 2 The secondary aim is to use a process evaluation to understand how it works, and for whom the program works.

The purpose of the process evaluation is to understand how it worked and for whom, and not if it worked. The investigators will combine in-house registrations from the municipality, clinician observations, individual interviews, and focus-group interviews to answer what works for whom and under which circumstances. This will give the investigators additional insights into the novel PSE intervention, shedding light on how it induces change and uncovering any potential unintended consequences. This will support future implementation pending results.

• Mean Pain intensity [Time frame: At 6 weeks, 3 months and 6 months]
• Pain interference [Time frame: At 6 weeks, 3 months and 6 months]
• Concept of pain [Time frame: At 6 weeks, 3 months and 6 months]
• Pain catastrophizing [Time frame: At 6 weeks, 3 months and 6 months]
• Fear of movement [Time frame: At 6 weeks, 3 months and 6 months]
• Patient specific functional limitation [Time frame: At 6 weeks, 3 months and 6 months]
• Patient impression of change [Time frame: At 6 weeks, 3 months and 6 months]
• Patient satisfaction with current symptom state [Time frame: At 6 weeks, 3 months and 6 months]
• Pain Self-efficacy [Time frame: At 6 weeks, 3 months and 6 months]
• Adverse events [Time frame: "through study completion, an average of 6 months".]