Optimising clinical trial methods for complex regional pain syndrome: a methodological framework (OptiMeth-CRPS).

INTRODUCTION: Complex regional pain syndrome (CRPS) is a rare, disabling pain disorder. Systematic reviews have identified a critical lack of high-quality clinical trial evidence to inform the management of CRPS. There is an urgent need to find solutions to the methodological challenges of undertaking clinical trials in CRPS. The aim of this project was to develop a methodological framework for optimising future clinical trials in CRPS (OptiMeth-CRPS). METHODS: An international network with expertise in the lived experience of CRPS, CRPS trials and evidence synthesis, and rare disease trial methods developed the framework using an "Experience and expertise" approach through an iterative process of (1) online and face-to-face meetings, (2) reviewing and approving meeting notes, and (3) revising draft manuscripts to develop the framework. RESULTS: The OptiMeth-CRPS methodological framework presents 9 key optimisation strategies for improving the methodological quality of CRPS trials. These include strategies for optimising (1) the trial team, (2) research questions, (3) trial governance and management, (4) trial design, (5) the trial population, (6) intervention and comparator groups, (7) trial outcomes, (8) data analysis, and (9) openness, transparency, and reporting. We highlight those optimisation strategies that specifically address the challenges of undertaking clinical trials in people with CRPS. CONCLUSION: A methodological framework for optimising clinical trials in CRPS has been developed. The OptiMeth-CRPS methodological framework may support the CRPS research community to undertake high-quality clinical trials and improve the quality of the evidence on which clinical decisions and guidelines for the management of CRPS are based.