Effectiveness and cost-analysis of a three-week multimodal inpatient pain treatment for children and adolescents suffering from chronic pain

INTERVENTION: All participants receive multimodal inpatient pain treatment (e.g. cognitive behavioural therapy, physiotherapy, music therapy). Participants will be randomly allocated to one of two groups differing in time intervals between first contact and hospitalisation (admission within 1 ‐ 5 days versus admission within 3 ‐ 4 weeks). The total duration of the treatments are three weeks. The total duration of follow‐ups for all arms are 12 months. The timepoints are as follows: 1. First contact (randomisation) 2. 3 ‐ 4 weeks after randomisation 3. 6 ‐ 7 weeks after randomisation 4. 6 months after randomisation 5. 12 months after randomisation CONDITION: Chronic pain disorder ; Signs and Symptoms ; Pain PRIMARY OUTCOME: Composite endpoint:; 1. Mean pain intensity in the last 7 days/4 weeks (adolescents on a Numerical Rating Scale [NRS], with 0 = no pain to 10 = maximal pain; children on a faces pain scale, with 0 = no pain to 10 = maximal pain); 2. Pain related disability (Pediatric Pain Disability Index [P‐PDI]): disability in daily activities due to pain on 12 items, rated on a 5‐point scale (1 = never to 5 = always)]; 3. School absence due to pain: school absence was assessed via parental report as the number of days the child missed school within the preceding 4 weeks SECONDARY OUTCOME: 1. Pain related coping (PPCI‐R: self report questionnaire); 2. Childs and parents pain related anxiety (FSBK‐K, PCS‐P: self report questionnaires); 3. Parents pain related behaviour (ISEV: self report questionnaire); 4. Number of physican appointments (parental report); 5. Pain medication (physicans report by pain medical history); ; Outcomes are measured at timepoints 1‐ 5, mentioned in the interventions section. INCLUSION CRITERIA: 1. Chronic pain patients fulfilling criteria for multimodal inpatient pain treatment 2. Age at enrolment between 9 and 18 years, either sex 3. Appropriate comprehension of German