The goal of this descriptive non-randomized feasibility study is to assess aspects of feasibility of the intervention arm in a planned full-scale randomized controlled trial testing the effectiveness of a self-management program for persons who have sustained a moderate to severe traumatic injury. All outcomes will be evaluated based on pre-defined success criteria. The main outcomes in the feasibility study are:

• Consent rate of eligible patients
• Drop-out rate
• Attendance rate in the program sessions

Secondary outcomes are the participants' acceptance, reception, and perceived usefulness. Other outcomes are fidelity and protocol adherence, as well as the feasibility of a telehealth version of the program and the data collection methods.

The participants will receive a group-based self-management program consisting of eight weekly 2.5-hour sessions delivered by a multidisciplinary team. The self-management program is manualized and includes psychoeducation, training in self-management skills and strategies, setting goals, action planning, and sharing of experiences. The participants will also complete the pre- and post-intervention assessments.

Background: Traumatic injuries, defined as physical injuries with sudden onset, are a major cause of distress and disability, with far-reaching societal consequences. A significant proportion of trauma survivors report problems and impaired health years after the injury. This includes impaired physical and mental health, difficulties in daily activities, and reduced health-related quality of life, which may subsequently limit participation in work/study, leisure activities, and family life. Consequently, these patients are often in need of complex rehabilitation and long-term follow-ups. The need to improve rehabilitation services and provision, including shared decision-making and self-management approaches, has been acknowledged. The World Health Organisation's (WHO) Rehabilitation 2030 initiative calls for strengthening and developing multidisciplinary rehabilitation. In line with the principles of user-involvement and patient-centred rehabilitation, strategies aiming to support self-management have received increased attention. Self-management refers to the systematic provision of education and supportive interventions by health care staff to increase patients' skills and confidence in managing their health problems. As recommended by the complex intervention framework presented by the Medical Research Council (MRC), a feasibility study will be performed as a preparation of a randomized controlled trial (RCT) on the effectiveness of a self-management support program.

Design and study settings: a non-randomized feasibility study of the intervention arm performed as a preparation for a pragmatic RCT testing the effectiveness of a self-management program using a mixed-methods design with 6-months follow-up. The feasibility study will be conducted at Oslo University Hospital and eligible patients who have sustained a moderate to severe traumatic injury will be included 3-4 months post-injury. Informed consent will be collected.

Intervention: The self-management program is manualized and integrates components from evidence-based rehabilitation strategies within relevant functional domains, to fit the symptom burden of the trauma population. It consists of eight 2-5-hour sessions delivered by a multidisciplinary team. The program will be delivered both face-to-face and in a telehealth version and patients will choose the delivery format based on their own preferences.

Aim: The overall aim is to set up the program, make necessary adjustment of the program, and study procedures in advance of the full-scale RCT. More specifically, feasibility of the intervention program and study procedures (including acceptability, protocol adherence, consent rates, dropout, attendance rate, participants' satisfaction with the program, and data collection methods) will be assessed.

Sample size and analyses: In the feasibility study, 10% of the estimated sample size in the intervention arm of the full-scale RCT will be included, which equals to 12 participants. The results will be evaluated according to pre-defined success criteria to determine feasibility and make necessary adjustments to the SMS program and study procedures in advance of the full-scale RCT.

To describe the study population, the following sociodemographic and injury-related variables will be recorded at baseline: age, gender, marital status, living conditions, educational level, description of pre-injury functioning and employment. Medical variables include comorbidities, diverse injury characteristics and trauma severity scores, length of hospitalisation and medical treatment modalities, and symptom burden along with screening of cognitive function.

Data collection methods and completion of the selected outcome measures will be assessed in the feasibility study. The following outcome measures are planned for the full-scale RCT, and will also be included in the feasibility study:

• Self-efficacy assessed using the Trauma Coping Self-Efficacy questionnaire
• Symptom burden assessed by the Rivermead Post-Concussion Symptom Questionnaire, Fatigue Severity Scale, Insomnia Severity Index, and Brief Pain Inventory Short Form
• Physical function assessed by the Short Physical Performance Battery and the International Physical Activity Questionnaire Short Form
• Cognitive function assessed by the Cognitive Failures Questionnaire and Cognitive items Rivermead.
• Emotional distress assessed by the Patient Health Questionnaire-9 & Generalized Anxiety Disorder-7 and Impact of Event Scale- Revised
• Return to work assessed by the full-time/part-time (percentage) or hours per week working
• Resilience assessed by the Resilience Scale for Adults
• Health status assessed by EuroQol five-dimensional questionnaire
• Individual injury related self-reported problem areas assessed by the target outcomes
• Evaluation of changes and intervention satisfaction assessed by the Patient Global Impression of Change and Visual Analogue Scales
• Disability assessed by the WHO Disability Assessment Scale
• General functioning assessed by the Glasgow Outcome Scale - Extended.
• Communication assessed by Communication with physicians and Health Literacy Questionnaire
• Health care utilization assessed by the type and frequency of health care services received

Inclusion Criteria:

1. Adults between 18-72 years residing in the southeast region of Norway
2. Admitted to OUH directly or after transfer from local hospitals within 72 hours of injury
3. At least a two-day hospital stay
4. Traumatic injury corresponding to a New Injury Severity Scale score (NISS) >9
5. Patients reporting injury-related symptoms, functional impairments, and/or difficulties with daily activities at discharge from Oslo University Hospital
6. Time since injury 3-4 months post-injury at inclusion.

Exclusion Criteria:

1. Cognitive function corresponding to a Mini Mental Status score <20 points
2. Severe psychiatric diseases or drug/alcohol dependence that require treatment
3. Complete spinal cord injury or isolated abdominal/thoracic injuries
4. Insufficient command of Norwegian.

Data are sensitive and will not be openly shared.