Ab1376 Osteoarticular Involvement in Multiple Myeloma: Prevalence and Risk Factors

Background: Osteoarticular (OA) involvement represents the most common extra-hematologic manifestation of multiple myeloma (MM). Objectives: This study aims to describe the OA manifestations during MM and identify its risk factors. Methods: We conducted a retrospective study including 126 multiple myeloma cases treated in our department over a 30-year period (1993–2023). Sociodemographic, clinical, and biological data were gathered. OA involvement was assessed through radiographic and/or magnetic resonance imaging (MRI) data. Results: The study included 126 patients with a mean age of 65.23±11.63 years 36–92, comprising 65 males and 61 females. Bone pain was present in 92.1% (n=116) with an average duration of 4 months. Mean erythrocyte sedimentation rate and C-reactive protein levels were 99.08 mm 3–190 and 27.74mg/l 0–196, respectively. Hemoglobin was below 10g/dl in 51.2% of cases, averaging 9.902±2.22 g/dl 5–13.9. Calcium levels exceeded 2.75 mmol/l in 20% of cases, averaging 2.49 ± 0.33 mmol/l. Mean creatinine level was 88.28 μmol/l 36–587. Plasmocyte rates, observed in sternal puncture or bone marrow biopsy, averaged 43.93% 5–80, with 31.7% exceeding 60%. Radiological osteolysis was found in 76.2% (n=96) of patients, with multiple lesions in 91 cases. Commonly affected bones were the skull (37.12%), pelvis (16.8%), and spine (12%). Diffuse osteosclerosis was identified in only two patients. Pathological fractures were present in 59.5% (n=75), including 15 peripheral fractures and 70 vertebral fractures, with 43.2% affecting the lumbar region (n=54) and 36.8% the dorsal region (n=46). Durie and Salmon prognostic classification distributed patients as follows: Stage IA (3.2%), Stage IIA (4%), Stage IIB (0.8%), Stage IIIA (72.2%), and Stage IIIB (18.3%). Plasmocyte rates in bone marrow were significantly higher in patients with multiple osteolytic lesions (36.4 vs 52.32%, p=0.016). Male gender was associated with higher onset of bone pain (OR=9.643, 95% CI 1.183–78.57, p=0.017). Stage III of the Durie and Salmon classification was associated with radiological osteolysis (Chi2=5.703, p=0.05). Conclusion: Articular involvement in multiple myeloma is polymorphic, ranging from bone pain to multiple pathological fractures. Evaluation of prognostic markers, such as plasmocyte rates and the Durie and Salmon prognostic classification, helps identify patients at risk of developing osteoarticular complications. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: None declared.