POS1378 COMPARISON OF DEMOGRAPHIC AND CLINICAL FEATURES OF FAMILIAL MEDITERRANEAN FEVER PATIENTS AND PATIENTS WITH AXIAL SPONDYLOARTHRITIS ACCOMPANYING FAMILIAL MEDITERRANEAN FEVER
Authors: M. Kiraci, E. Bilgin, E. Duran, B. Farisoğullari, E. C. Bolek, G. K. Yardimci, Z. Özsoy, G. Ayan, G. Sandal Uzun, B. Balci Peynircioglu, O. Karadag, A. Akdoğan, Ş. A. Bilgen, S. Kiraz, A. İ. Ertenli, U. Kalyoncu, L. Kiliç
Journal: Annals of the Rheumatic Diseases (2021)

Background: The rate of co-occurrence of Familial Mediterranean Fever (FMF) and axial spondyloarthritis (axSpA) in adults is reported ranging from 0.5% to 7.5%. The clinical implications of this co-occurrence in the course of FMF is still a research question. Objectives: To compare of demographic and clinical features of patients with FMF and FMF+axSpA. Methods: A total of 9630 FMF patients was detected according to the ICD-10 code (E85.0) of FMF in Hacettepe University Hospital database. 241 of these patients also had axSpA according to the ICD-10 code (M45). FMF diagnosis was confirmed by Tel-Hashomer criteria. AxSpA was diagnosis was confirmed by either presence of sacroiliitis on sacroiliac radiography according to the Modified New York Criteria (mNY) or presence of active sacroiliitis according to ASAS criteria on magnetic resonance imaging. 136 patients were confirmed according to these criterias as having FMF+axSpA. As a control group, 231 consequent FMF patients without axSpA recorded on the “FMF in Central Anatolia (FiCA) database” and followed up at our center were included in the analysis. Demographic and clinical features of those patients in both groups were compared. p&lt;0.05 was considered as statistically significant, correction for multiple comparisons was not performed. Results: 136 patients were included in FMF+axSpA group and 231 patients were included in FMF group. 114 (83.8%) patients in FMF+axSpA group had radiographic sacroiliitis according to mNY criteria; median cervical mSASSS was 0 (available for 49 patients, min-max, 0-36), median lumber mSASSS was 4 (available for 121 patients, min-max, 0-36), 33 (27%) patients had cervical or lumber syndesmophyte. Twenty-six (19.1%) of these patients had radiologically documented inflammatory hip disease 12 (8.8%) of these patients underwent total hip replacement. Female gender was more prevalent in FMF+axSpA group (53.7% vs 32.5%, p&lt;0.001). Age at FMF symptom onset and diagnosis were earlier in FMF patients; however, symptom and disease durations were longer in FMF+axSpA group in our study cohort (Table 1). Frequency of FMF signs and symptoms were comparable except the rate of pleuritis was higher in FMF patients compared to FMF+axSpA group (p=0.003). Amyloidosis was more prevalent in FMF+axSpA group (6.6% vs. 1.7%, p=0.014). Results of MEFV gene analysis were available for 273 patients. Although presence of M694V mutation (either in 1 allele or 2 alleles) was comparable in 2 groups, homozygous M694V mutation was more prevalent in FMF+axSpA group (39.8% vs. 28.9%, p=0.02). Conclusion: The coexistence of spondyloarthritis in FMF patients appears to be associated with the increased prevalence of amyloidosis. The inflammatory burden of a second disease and the increased prevalence of the homozygous M694V mutation may explain this risk. Table 1. Comparison of demographic and clinical features of two groups. FMF+AxSpA (n=136, 37.1% ) FMF (n=231, 62.9% ) p Female, n(% ) 73 (53.7) 75 (32.5) &lt;0.001 Age at FMF symptom onset, years med (IQR ) 12 (5-20) 10 (6-18) 0.046 Symptom duration, years, med (IQR ) 24 (18-32) 20 (14-29) 0.007 Age at FMF diagnosis, years, med (IQR ) 24 (13-33) 20 (11-30) 0.10 Duration after diagnosis, years, med (IQR ) 16 (10-22) 13 (7-17) &lt;0.001 FMF signs and symptoms, n(% ) -Fever 128 (94.1) 204 (88.3) 0.067 -Abdominal pain 123 (90.4) 217 (93.9) 0.21 -Pleuritis 31 (22.8) 87 (37.7) 0.003 -Pericarditis 3 (2.2) 2 (1.0) 0.34 -Arthritis 64 (47.1) 92 (39.8) 0.17 -Erysipelas 24 (17.6) 38 (16.5) 0.77 -Febrile myalgia 9 (6.6) 13 (5.6) 0.70 Inflammatory back pain, n(% ) 92 (67.6) 26 (11.3) &lt;0.001 Inflammatory bowel disease, n(% ) 6 (4.4) 4 (1.7) 0.12 FMF family history, n(% ) -Any degree 66 (48.5) 137 (59.8) 0.04 -First degree 48 (35.8) 97 (42.0) 0.24 -Second degree 25 (18.7) 86 (37.2) &lt;0.001 Number of attacks at recent year, med (min-max ) 1 (0-12) 1 (0-10) 0.13 Amyloidosis 9 (6.6) 4 (1.7) 0.014 M694V status (N=273 ) -Present (one or two allels ) 91 (80.5) 120 (75.0) 0.28 -Two allels 45 (39.8) 43 (28.9) 0.02 Disclosure of Interests: None declared