Preliminary identification of key clinical domains for outcome evaluation in fibromyalgia using Delphi methods: the Italian experience

Objective: Fibromyalgia (FM) is a complex syndrome that affects at least 2% of the adult population in Italy. It is characterised by chronic widespread musculoskeletal pain often accompanied by multiple other symptoms. The aim of this study was to identify a set of clinical domains for FM considered relevant by both clinicians and patients using a consensus process. Methods: Consensus was achieved using the Delphi method based on questionnaires and systematic, control- led opinion feedback. The Delphi exercises involved a panel of 252 rheumatologists and 86 patients with FM as defined by the American College of Rheumatology criteria. All of the patients and clinicians were asked to rank the relative priority of different domains of FM. The content validity index (CVI) was used to establish the percentage agreement. The importance of each item was ranked on a 0-3 Likert scale. The frequency, mean relevance scores and frequency importance product were also calculated. Results: The Delphi exercise revealed that the paitients’ highest-ranked domains were similar to those of the clinicians: the exceptions were tender point intensity (considered relevant by the clinicians but not by the pa- tients) and environmental sensitivity (considered important by the patients but was not by the clinicians). A final eight-item model receiving adequate validity remained in the assessment instrument. Conclusions: The Delphi exercises identified and ranked relevant key clinical domains that need to be assessed in FM research. On the basis of these results, a new patient-reported composite outcomes index can be devel- oped and used in clinical trials.