Development of the autoinflammatory disease damage index (ADDI)

Objectives Autoinflammatory diseases cause systemic inflammation that can result in damage to multiple organs. A validated instrument is essential to quantify damage in individual patients and to compare disease outcomes in clinical studies. Currently, there is no such tool. Our objective was to develop a common autoinflammatory disease damage index (ADDI) for familial Mediterranean fever, cryopyrin-associated periodic syndromes, tumour necrosis factor receptorassociated periodic fever syndrome and mevalonate kinase deficiency. Methods: We developed the ADDI by consensus building. The top 40 nrollers of patients in the Eurofever Registry and 9 experts from the Americas participated in multiple rounds of online surveys to select items and definitions. Further, 22 ( parents of ) patients rated damage items and suggested new items. A consensus meeting was held to refine the items and definitions, which were then formally weighted in a scoring system derived using decision-making software, known as 1000minds.Results More than 80% of the experts and patients completed the online surveys. The preliminary ADDI contains 18 items, categorised in the following eight organ systems: reproductive, enal/amyloidosis, developmental, serosal, neurological, ears, ocular and musculoskeletal damage. The categories renal/ amyloidosis and neurological damage were assigned the highest number of points, serosal damage the lowest number of points. The involvement of ( parents of ) patients resulted in the inclusion of, for example, chronic musculoskeletal pain.Conclusions An instrument to measure damage caused by autoinflammatory diseases is developed based on consensus building. Patients fulfilled a significant role in this process.