Background/Purpose: Adults with sterile bone inflammation are variably labelled as Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis (SAPHO)-syndrome, chronic nonbacterial osteomyelitis, chronic recurrent multifocal osteomyelitis (CRMO), pustulotic arthro-osteitis (PAO), or sternocostoclavicular hyperostosis (SCCH). We developed a first consensus statement on disease definition and the preferred name, together with a clinical practice guideline (CPG) on diagnosis and treatment, integrating existing evidence and multidisciplinary expert opinion, as well as a research agenda.

Methods: This initiative comprised a systematic literature review and GRADE-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 for “adults with sterile bone inflammation”, based on which panel members and patient representatives propose the diagnostic term “chronic nonbacterial osteitis” (CNO). As overarching principle, care for adult CNO is ideally multidisciplinary and situated at expert centers. The CPG addresses the initial evaluation of suspected adult CNO patients, highlighting the limited role of laboratory investigations and bone biopsies, and the crucial role of imaging. Initial imaging is preferably done by magnetic resonance imaging, or otherwise by computed tomography combined with nuclear imaging. Specific considerations are included regarding the role of (routine) whole-body imaging. Treatment goals and outcome measures emphasize patient-reported indices like pain, especially since the prognostic value of persistent radiologic activity is yet unknown. A suggested treatment algorithm for adults with symptomatic CNO includes the initial use of non-steroidal anti-inflammatory drugs/cyclooxygenase 2-inhibitors in most patients, whereafter bisphosphonates or tumor necrosis factor alpha inhibitors can be considered. Typically, bisphosphonates are preferred as first-choice, though choice depends on individual patient factors and the presence of additional inflammatory features. The CPG further discusses follow-up, management of adverse events and complications, and a future research agenda.

Conclusion: This consensus statement and CPG is intended to support health care professionals world-wide in their care for adults with CNO. It also lays the groundwork for establishing international patient registries, translational research lines, and multicentre trials, all of which are urgently required.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/2024-clinical-practice-guideline-for-the-diagnosis-and-treatment-of-chronic-nonbacterial-osteitis-cno-in-adults/