Stefan Elbers

105 Self-management for patients with chronic pain time self-reports of thoughts, feelings or activities can be obtained – could provide a more detailed insight in longitudinal individual response patterns to treatment (Vlaeyen et al., 2001; Maes et al., 2015). Second, Keogh et al. (2015) attribute the limited effectiveness and large variety in content and delivery of self-management interventions to limited and inconsistent application of behaviour change theory throughout the intervention. Increased self-efficacy is often mentioned as an explanatory (mediating) factor, but it remains unclear how more confidence in the capability to live a meaningful life with pain would explain all post- intervention results, including pain intensity. In particular, as we only identified a post- intervention trend for self-efficacy favouring self-management interventions, other mechanisms that have not yet been identified could be responsible for the small short- term effects on pain intensity and physical function. We believe that future research on moderators and mediators of the relationship between self-management interventions and outcome measures could provide insight in how to optimize the effectiveness of this type of intervention. Third, despite the limited effectiveness of stand-alone generic interventions, self- management skills such as problem-solving, action-planning and decision making have the potential to reinforce existing pain management treatments. Indeed, self-management is regarded as a common component in interdisciplinary pain management programmes and is expected to facilitate more active and resilient coping (McCracken and Turk, 2002; Turk et al., 2011). Future studies should investigate the interaction between self- management skill training and disease-specific treatment components. This would lead to more insights on the contribution of self-management skill training to long-term effects of pain management programmes. Strengths and Limitations Although all included studies focused on enhancing generic self-management skills in order to improve clinical outcomes, there was a large variation on how to achieve and measure this. As a consequence, the methodological heterogeneity of the included studies negatively influenced the robustness of the outcomes. Therefore, the overall quality of evidence was downgraded for each comparison on indirectness. This also caused us to select a random-effects model, which made the pooled results difficult to interpret (Higgins and Green, 2011), even when the effect was re-expressed on the measurement scale of interest. Although this method provides an indication of the clinical importance of the effect, it cannot be regarded as a conclusive result. This is mainly because MCIDs are concerned with the effect at individual patient level rather than on mean scores at group level. However, an advantage of statistical pooling over qualitative forms of synthesis is that sample