LAUSR

OBJECTIVE To compare the demographic, clinical, and radiological features of patients with axial spondyloarthritis (axSpA) accompanying familial Mediterranean fever (FMF) to patients with each condition alone. METHOD Hacettepe University Hospital database was screened regarding ICD-10 codes for FMF (E85.0) and axSpA (M45). The diagnosis of FMF was confirmed by Tel-Hashomer criteria, and axSpA by the presence of sacroiliitis according to the modified New York criteria or active sacroiliitis on magnetic resonance imaging. As control groups, 136 gender-matched, consequent FMF patients without axSpA and 102 consequent axSpA patients without FMF previously treated with any biological agents were included in the analysis. RESULTS In patients with FMF + axSpA compared to the axSpA group, age at axSpA symptom onset and age at diagnosis were lower [median with interquartile range (IQR): 21 (17-30) vs 27 (21-37), p < 0.001; 23 (21-38) vs 32 (24-43) years, p = 0.001], moderate to severe hip disease and total hip replacement were more prevalent (23.4% vs 4.7%, p < 0.001; 11.2% vs 2.8%, p = 0.016). In patients with FMF + axSpA compared to the FMF group, age at FMF symptom onset and age at diagnosis were higher [13 (6-30) vs 11 (5-18), p = 0.057; 23 (13-33) vs 18 (10-31) years, p = 0.033] and amyloidosis was more prevalent (6.6% vs 2.2%, p = 0.076). Although the M694V variant (in one or two alleles) was more prevalent in the FMF + axSpA group, the difference was not statistically significant. CONCLUSION In patients with FMF + axSpA, the age of onset of axSpA was significantly earlier, moderate to severe hip involvement and amyloidosis were more common than in patients with each condition alone.