MMRP Analysis

We appraised the strength of the evidence across published SRs and MAs of MMRPs for prevalent clinical pain conditions and our primary analysis found that among 134 associations less than half produced significant results at P-value ≤0.05 under random-effects modelling. The proportion of significant results shrunk to almost 11% when a more strict threshold was applied (P-value <0.001). Additionally, none of the statistically significant results presented either convincing or highly suggestive evidence. Only a trivial quantity was supported by suggestive evidence. These pertained to MMRPs associations merely for LBP and mainly for short-term outcomes. However, only one of those associations regarding the long-term effects on work absenteeism

Some of the evidence, though limited, may reveal probable associations between MRRPs and the outcomes of pain and disability. The possibility that MMRPs increases the odds of the return to work sounds also promising and should be tested in future large RCTs for solid conclusions. Our results, in further, highlight that MMRPs may have more favourable effects on short-term outcomes compared to medium and long- term outcomes; assumptions which require further assessment e.g., with respect to methods for maintaining gains after MMRPs. Subsequently, stakeholders such as clinicians, researchers, and health policy makers should be aware that findings stemming from few meta-analyses with restricted numbers of RCTs should be treated with caution. Indeed, there is an ongoing discussion in relation to meaningful ways of the clinical interpretation of the results of the published meta-analyses and their reported outcomes (79). Health policy makers and expert panels should take into consideration that the evidence is limited adjusting as well for the cost-effectiveness of these treatments. Concerns regarding the economic burden of MMRPs have repeatedly described in the literature (19, 80). However, adjusting for costs may not be as simple as that; the implementation of larger RCTs may be not practical due to cost barriers. On the other hand, the consideration of such costs

Many RCTs report on several outcomes which are seldom divided into primary and secondary outcomes; in a Swedish SR (not included here) an average of nine outcomes/RCT was found (81). MMRP is a complex treatment with broad goals and as a result, it is very unlikely that changes in nine outcomes are independent of each other. The question arises how to determine if positive results are obtained or not in an RCT of MMRP; evaluating one outcome at a time, as done here and in most RCTs, SRs and MAs, may not be the most accurate process, since the treatment was not designed just to target on one outcome. Moreover, small changes in nine variables may be more important for the patient than one prominent change in one out nine