Expert consensus recommendations for the diagnosis and treatment of chronic non-bacterial osteitis (CNO) in adults.

Background: There is considerable practice variation in labelling, diagnosis and treatment of adults with sterile bone inflammation. We developed a expert consensus recommendations on the disease definition, diagnosis and treatment of this rare condition.

Methods: Systematic literature review and Grading of Recommendations, Assessment, Development and Evaluations-based appraisal of evidence, two Delphi surveys and three digital and in-person consensus meetings with a multidisciplinary expert panel and patient representatives.

Results: A consensus disease definition was developed and the term 'chronic non-bacterial osteitis' (CNO) is proposed to describe adults with sterile bone inflammation. For initial imaging evaluation of adults with suspected CNO, the panel recommends MRI or otherwise CT combined with nuclear imaging. Whole-body imaging at initial evaluation can be considered for diagnostic and prognostic purposes. Suggested first-line treatment in adults with active CNO includes nonsteroidal anti-inflammatory drugs/cyclooxygenase 2-inhibitors. Second-line treatment preferably consists of intravenous bisphosphonates, and otherwise tumour necrosis factor-α inhibitors. Choice between them should be individualised, considering the presence of additional inflammatory features. The panel further discusses outcome measures, follow-up and management of adverse events and complications.

Conclusions And Future Perspectives: These expert consensus recommendations are intended to support healthcare professionals worldwide in their care for adults with CNO. They also lay the groundwork for establishing international patient registries, translational research lines and multicentre trials, all of which are urgently required.