Diagnostic delays in familial Mediterranean fever: a Juvenile Inflammatory Rheumatism (JIR) cohort study

Several studies reported that Familial Mediterranean Fever (FMF) diagnosis may be missed or delayed even in countries with a high FMF prevalence. Our aim was to study on a large cohort of European FMF patients the frequency and associated factors of diagnosis delay. Clinical data were extracted from the Juvenile Inflammatory Rheumatism (JIR)-cohort. All FMF patients fulfilled Livneh Criteria and had been sequenced for MEFV exon 10. FMF-diagnostic delay (d-FMF) was defined as the duration between the onset of the symptoms and the diagnosis of more than 10 years. 960 FMF patients were enrolled: delayed diagnosis (d-FMF) was noted in 200 patients (20%). d-FMF patients were significantly older compared to non d-FMF with a median age of 46.4 years old vs. 15.5 ( p