CO:07:1 | Assessing bone fragility in systemic sclerosis: results of the Sclerobone multicentric study

Giammarco De Mattia¹, Cristina Di Nicola², Davide Rozza², Manuel Sette³, Veronica Gerli³, Ludovica Pisapia¹, Chiara Sgorbini¹, Giulia Botticella⁴, Pamela Bernardini⁵, Francesca Bottazzi⁶, Francesca Lalli⁸, Luca Idolazzi⁷, Laura Bogliolo⁶, Monica Cesarotti⁸, Alessandra Rossi¹, Alessandra Della Rossa¹, Andrea Giusti⁴, Serena Guiducci⁵, Carlo Alberto Scirè², Addolorata Corrado⁹, Nicoletta Del Papa³, Marta Mosca¹, Chiara Crotti³, Maurizio Rossini⁷, Maurizio Mazzantini¹. | ¹UO Reumatologia, Dipartimento di Specialità Mediche e Chirurgiche, Azienda Ospedaliero-Universitaria Pisana, Pisa; ²Centro Studi SIR, Società Italiana di Reumatologia, Milano; ³UO Reumatologia, ASST Gaetano Pini-CTO, Milano; ⁴SC Reumatologia, Ospedale La Colletta, Azienda Sanitaria Locale 3 Liguria, Arenzano (GE); ⁵SOD Reumatologia, Azienda Ospedaliero-Universitaria Careggi, Firenze; ⁶SC Reumatologia, Fondazione IRCCS Policlinico San Matteo, Pavia; ⁷UOC Reumatologia, Azienda Ospedaliera Universitaria Integrata di Verona; ⁸SSD Reumatologia, Azienda Sanitaria Locale Perugia; ⁹Clinica Reumatologica Universitaria, Azienda Ospedaliero Universitaria di Foggia, Italy

Background: Considering the limited and conflicting data regarding prevalence and risk factors of osteoporosis (OP) in systemic sclerosis (SSc), we aimed at evaluating a large population of patients at several Italian institutions. Enrollment started in October 2024 and will end in October 2025.

Materials and Methods: We are investigating the presence of OP in randomly selected subjects fulfilling the 2013 ACR/EULAR SSc classification criteria using a partially retrospective design. Exclusion criteria include ongoing pregnancy, cancer, metabolic bone diseases other than OP, and therapies interfering with bone health; exceptions are chronic kidney disease, anti-osteoporotic drugs, glucocorticoids (GC), and proton pump inhibitors. OP was defined as history of fragility fractures (FX) and/or of bone mineral density (BMD) values with T-scores < -2.5 or Z-scores < -2.0. BMD is evaluated using DXA scans within 12 months before enrollment or performed at enrollment. Demographic and anthropometric data, menopausal status, dietary calcium intake, Charlson Comorbidity Index (CCI), and concurrent medications are assessed. Sarcopenia, when detected with the SARC-F+EBM questionnaire, is evaluated with functional tests such as hand grip strength, chair stand test, and gait speed. A characterization of SSc is performed, including age at diagnosis, disease duration, and organ involvement. The cumulative SSc-related damage is expressed with the Scleroderma Clinical Trials Consortium Damage Index (SCTC-DI). We provide the results of the pre-planned interim analysis performed in April 2025; the final analysis is planned in October 2025.

Results: The interim analysis focused on 315 patients, with a mean age at enrollment of 63.2±11.3 years. They were diagnosed with SSc at a mean age of 51.2±12.4 years and had been affected for a median time of 10 years (interquartile range - IQR 12). Females made up the majority (n = 292; 92.7%) of the cohort, with 266 (91.1%) having been postmenopausal for a mean time of 17.3±10.1 years. The mean BMI was 24.3±4.4 kg/m², and 16.8% of patients were sarcopenic. Dietary calcium intake was insufficient (<700 mg) in 70.4% of cases, and optimal (>1000 mg) only in 3.9%. Approximately 30% of patients were taking GCs. The mean CCI score was 3.7±1.6, suggesting a 10-year mortality risk of approximately 40%. The median SCTC-DI score was 3 (IQR 3). Our main finding was that OP affected 136 (43.2%) subjects: 84 (61.8%) had reduced BMD values only, and 52 (38.2%) had a history of FX.

Conclusions: Our interim analysis showed that 43.2% of patients were affected by OP, suggesting a potentially high burden in SSc. To identify any predictive factors of OP in SSc, the final analysis will include correlations with SSc organ involvement, biochemical markers, densitometric values, sarcopenia, body composition parameters, and FX risk calculations with the DeFRA algorithm.