AB1021 FACTORS ASSOCIATED WITH FRAGILITY FRACTURE IN PATIENTS WITH SYSTEMIC MASTOCYTOSIS: DATA FROM AN INCEPTION COHORT IN A SINGLE CENTRE

Background Systemic Mastocytosis (SM) is a very rare disease. Most common manifestations are skin related or anaphylaxis, however almost one third of patients may present with concomitant osteoporosis (OP) resulting in fragility fracture (FF) around 5 -37% affecting lumbar spine (LS) young men. Alcohol consumption, high serum tryptase level, and low femoral T score have been described as risk factors but there some discrepancies between studies. 1-2 Objectives Our primary objective was to identify associated FF SM. Methods We analysed all consecutive attending multidisciplinary clinic up April 2021 SM diagnosis according the 2001 WHO criteria. collected demographic data, general for OP, cutaneous, bone involvement laboratory data level. Bone defined densitometric OP (T ≤ - 2.5) FF. Normally distributed variables means (SD) dichotomous number frequencies. Comparison without performed using t-test Chi 2 when needed. Results Seventeen included this preliminary analysis. Four (24%) presented FF, them vertebral fractures identified by plain radiographies.Two men two women they were older versus (Table 1), OP. All basal most other MS symptoms (cutaneous, anaphylaxia). FRAX tool useful only patient predict risk. The do not met criteria specific characteristics these Table 2. 1 Population (N = 17) Without 13) With (N=4) P Male, n (%) 9 (53%) 7 (54%) (50%) 0.89 Age at first symptoms, years, mean 37.6 (21.1) 33.0 (20.2) 58.1 (10.1) 0.05 diagnosis, 47.7 38.8 (20.9) 59.7 (13.1) 0.08 Ever smoker, 6 (35%) 4 (30.8%) 0.48 Alcohol, (11.76%) (7.69%) (25%) 0.34 BMI, 26.5 (4.3) 25.3 (4.0) 30.6 (2.0) 0.02 BMI<19kg/m2, (6%) (7%) 0 (0%) 0.56 Cutaneous mastocytosis, 8 (47%) (38.5%) 3 (75%) 0.20 Anaphylaxia, (46.1%) Digestive (53.5%) 0.31 Basal >11,4 12 (70.6%) (61.5%) (100%) 0.14 tryptase, 20.20 (18.33) 10.68 (20.75) 22.85 (7.64) 0.75 General present, (29%) Femoral score, -1.03 (1.22) -3.82 (1.36) -1.86 (1.23) 0.12 Lumbar -1.06 (1.57) -5.27 -1.95 (2.08) Z -0.34 (1.05) -1.79 (1.44) -0.75 (0.65) 0.39 -0.30 (1.88) -5,38 -0.67 (2.96) 0.66 global fracture, 2.27 (2.52) 2.34 6.83 (7.82) 0.11 hip 0.23 (1.01) (0.27) 2.1 (1.92) 0.18 Characteristics Fragility Fracture four Mastocytosis. Patient Gender Localization Severity Time 65 Male D6,D8,D10,D11, L1 Mild2 Moderate years prior 81 Female D4,D8,D12, Mild3 Severe after D4,D11 Unknown 42 D7,D8,D9,D11,D12, L1,L2,L3,L5 Moderate3 At time Conclusion Twenty five percent (multiple, located dorsal spine, OP). should always be considered differential presence especially no another factor associated. References [1]van Doormaal JJ. J Allergy Clin Immunol. 2013;131(5):1429-31 e1 [2]van der Veer E. 2014;134(6):1413-21. Disclosure Interests None declared