Comparison of demographic, clinical and radiological features of patients with axial spondyloarthritis accompanying familial mediterranean fever and patients with familial mediterranean fever and patients with axial spondyloarthritis

The aim of this study is to reveal the demographic, clinical and radiological characteristics of patients with Axial Spondyloarthritis (SpA) accompanying Familial Mediterranean Fever (FMF) and to compare of these features patients with FMF and patients with axial SpA. Patients who were diagnosed with axial SpA accompanying FMF (n=136), axial SpA (n=102) and FMF (n=136) admitted to our clinic between 01.01.2014 and 31.07.2019 were included in the study. Clinical and laboratory data which were already available before were recorded for all patients. Data collected retrospectively were evaluated with appropriate statistical methods. As a result of analysis, in FMF-Axial SpA group; median cervical mSASSS was 0 (Q1-Q3, 0-36), median lumber mSASSS was 3 (Q1- Q3, 0-7), 33 (27%) patients had cervical or lumber syndesmophyte and 5 (%4,1) patients had total ankylosis. Twenty-six (19,1%) of these patients had radiologically documented inflammatory hip disease, twelve (8,8%) of these patients underwent total hip replacement. Age at FMF and axial SpA symptom onset and diagnosis were earlier in M694V positive AAA-Axial SpA patients compared to M694V negative patients (p<0,05). In FMF-Axial SpA patients, compared to the FMF group, fever was more frequent, pleuritis was lower, FMF diagnosis age was later, and duration of disease after diagnosis and symptoms were longer (p<0,05). The most common M694V mutation was seen in both groups, and the frequency of M694V allele and homozygous M694V mutations was higher in FMF-Axial SpA patients. However, the difference was not statistically significant. Axial disease onset and diagnosis age were earlier and the duration of the disease was longer in patients with FMF-Axial SpA compared to patients with axial SpA (p<0,05). Radiographically, the frequency of advanced stage sacroiliitis, lumbar syndesmophyte, moderate to severe hip involvement, hip prosthesis and amyloidosis was higher in the FMF-Axial SpA group (p <0.05). Whether FMF is a triggering factor for SpA, sacroiliitis is a feature of FMF or co- existence of this two disease is still controversial. Key words: Spondyloarthritis, axial spondyloarthritis, familial mediterranean fever