P092 One-year post-diagnosis outcome in a national chronic recurrent multifocal osteomyelitis/chronic non-bacterial osteomyelitis cohort

CRMO, also known as CNO, is an autoinflammatory condition affecting the bones of children. There is a wide spectrum of clinical presentations, ranging from singular lesions to relapsing, multifocal, or continuous disease. There is currently a lack of prospective study on the short to medium term disease outcome. The primary aim of this study was to understand the one-year post-diagnosis outcome in a prospectively identified national cohort of patients with CRMO/CNO in the United Kingdom and Republic of Ireland.

We conducted monthly surveys among all paediatric consultants and paediatric orthopaedic surgeons through British Paediatric Surveillance Unit and British Society for Children’s Orthopaedic Surgery to identify children and young people (<16 years) newly diagnosed with CRMO/CNO between October 2020 and November 2022. Standardised questionnaires were sent to reporting clinicians to collect detailed clinical information about each case within a few months of diagnosis (baseline) and one-year post-diagnosis. The responses were collated, and data were analysed using R.

Over the initial 25-month surveillance period, 185 children and young people with CRMO/CNO were identified. One-year follow-up questionnaires were received from 120/185 (65%) cases. Disease courses within the first year were categorised by the primary clinicians caring for the patients as continuous (23/113; 20%), recurrent (52/113; 46%) or a stand-alone episode (38/117; 34%). Disease control compared to baseline was reported to have improved in 104/115 (90%) of cases. At one-year 47/115 (41%) of patients were in remission, of which 38% are currently not taking any medication, and 32% are taking NSAIDs only. Overall, at one-year, 38/107 (36%) were not on any medication (including analgesics), and 34/107 (32%) were on NSAID alone (with or without other analgesics). There was no difference in one-year outcome between patients treated with pamidronate (n = 30) or those with zoledronate (n = 21). The average BMI percentile increased from baseline to one-year follow up (p = 0.021) although the increase was no longer significant after removing patients who had ever taken steroid treatment. There was an overall trend towards improved mobility, although this was not statistically significant. Average school attendance was higher at one-year follow up. Reported complications at one-year follow-up included pathological fractures (1/113; 0.88%) and bone deformity (4/113; 3.5%). Multivariate logistic regression analysis did not identify any presenting features that were significantly associated with better or worse one-year outcome.

The majority of children diagnosed with CRMO/CNO have disease relatively well controlled one-year post-diagnosis, as evidenced by clinicians’ perspectives on disease control and the majority of patients being treated only with NSAIDs, or no medication. A trend towards functional improvement was observed.

S. Sayers: None. D. Chia: None. A. Toms: None. A. Sanghrajka: None. A. Ramanan: Consultancies; Abbvie, Eli Lilly, Pfizer, Novartis, SOBI, UCB. O. Killeen: None. C. Ilea: None. C. Pain: None. N. Martin: None. K. Armon: None. C. Suo: None.