Stefan Elbers

32 Chapter 2 of bias, unless we found a clear indication of a limited impact of that item on the overall study outcome. The risk of bias form, including the scoring instructions, are available in the online multimedia appendix. Data Analysis The data extraction form included sample size (per measurement moment), age, sex, pain duration, nationality, method of recruitment, patient eligibility criteria, exclusion criteria, study design, type of outcome measures, and outcomes for all available time points on measurement instruments of interest. If treatment intensity was expressed in days, we assumed 6 hours of treatment per day. Because IMPT programmes are generally considered as a treatment of last resort, we specifically paid attention to obtaining information on attrition (Jeffery et al., 2011). We obtained pre, post and final follow-up sample sizes to calculate attrition rates for post-treatment and follow-up. When a cohort presented data for two or more outcome measures within one domain, we selected the most commonly used instrument. Descriptive Analysis. To investigate the heterogeneity between the included IMPT programmes, study, patient and intervention characteristics were summarized in tables. Intervention descriptions were extracted and each separate component was then classified into one of 10 possible categories. Education referred to modalities that were primarily concerned with transfer of information from healthcare providers or experts to patients. All modalities regarding physical training, such as stretching, hydrotherapy and walking were categorized as exercise. Graded activity was only coded if the modality explicitly used the term graded activity or if the activities gradually and time-contingent increased after a baseline measurement. Modalities that described (cognitive) behavioural approaches, including problem solving training, exposure in vivo, rational emotive therapy or ACT were classified as (cognitive) behavioural treatment. Breathing techniques, autogenic training, mindfulness, and applied relaxation techniques were classified as relaxation. Modalities that mainly focused on training general coping skills and self-regulation were categorized as self-management skills. This included, goal setting activities, general pacing techniques, structuring of daily activities and ergonomics. Pharmacological treatment was only coded when medication was provided in response to chronic pain. Medication withdrawal procedures were coded as 'other'. Workplace visits, and ergonomic advice at the workplace were coded as workplace advice. The category body awareness included physical awareness and psychomotor exercises that aimed to improve the recognition of bodily signals. The last category – team meetings – was only coded when the patient actively participated in the team meetings. The categories were inductively developed by first extracting and then clustering the modalities of the first search into global categories (by SE and SK). In the final dataset, these 10 categories covered more than 90% of the treatment modalities.