Clinical studies on multimodal pain therapy. Standardized measurement of therapy outcomes with a core outcome set

Decision making in evidence-based medicine is based on general data on therapy outcomes as well as the effectiveness and safety in specific patient populations. Typically, findings concerning therapy outcomes from different studies are aggregated for a final conclusion. In this context a comparison of results is hampered by studies in which therapy outcomes are heterogeneously measured. Such methodological challenges exist for almost all areas of medical treatment, as well as for multimodal pain therapy (MMPT). Through establishing core outcome sets (COS) the required standardization of measurement of therapy outcomes in clinical research can be achieved. A COS is an evidence-based and consented minimum set consisting of outcome domains (i.e. partial aspects of the medical condition to be investigated, which have to be measured in order to give the best possible demonstration of therapy outcome of an intervention) accomplished by valid, reliable and sensitive measurement instruments which should be applied in each clinical trial. No such COS has so far been found for MMPT. The aim of this article is to give an overview about currently recommended methodological approaches to develop a COS accompanied by a brief introduction about existing COS initiatives focusing on chronic pain. The existing COS recommendations are discussed and conclusions are drawn on whether existing recommendations could also be applied for MMPT. Finally, the impact of healthcare research in Germany on a standardized assessment of therapy outcome in MMPT is outlined.