Development of a core outcome set for myelodysplastic syndromes - a Delphi study from the EUMDS Registry Group.

Treatment options for myelodysplastic syndromes (MDS) vary widely, depending on the natural disease course and patient-related factors. Comparison of treatment effectiveness is challenging as different endpoints have been included in clinical trials and outcome reporting. Our goal was to develop the first MDS core outcome set (MDS-COS) defining a minimum set of outcomes that should be reported in future clinical studies. We performed a comprehensive systematic literature review among MDS studies to extract patient- and/or clinically relevant outcomes. Clinical experts from the European LeukemiaNet MDS (EUMDS) identified 26 potential MDS core outcomes and participated in a three-round Delphi survey. After the first survey (56 experts), 15 outcomes met the inclusion criteria and one additional outcome was included. The second round (38 experts) resulted in six included outcomes. In the third round, a final check on plausibility and practicality of the six included outcomes and their definitions was performed. The final MDS-COS includes: health-related quality of life, treatment-related mortality, overall survival, performance status, safety, and haematological improvement. This newly developed MDS-COS represents the first minimum set of outcomes aiming to enhance comparability across future MDS studies and facilitate a better understanding of treatment effectiveness.