The Effect of Clinical and Genetic Variables of Familial Mediterranean Fever Patients: Real Life Data

Background: The Eurofever/the Pediatric Rheumatology International Trials Organization (PRINTO) classification criteria for familial Mediterranean fever (FMF) include a combination of clinical symptoms and genotype. The pathogenicity of gene variants associated with FMF is categorized by the International Study Group for Systemic Autoinflammatory Diseases (INSAID) classification criteria. Objective: The aim of this study was to evaluate the real-life impact and usefulness of the Eurofever/PRINTO classification criteria and the INSAID classification criteria in patients with FMF and their impact on treatment management. Methods: In this medical records review study, the files of FMF patients who met the Eurofever/PRINTO classification criteria were reviewed. The MEFV (MEditerranean FeVer) variants were grouped according to the INSAID classification criteria. Results: Of the 1062 patients, the female-to-male ratio was 1:1.01. In group 1, there were 150 patients (14.1%) who met the clinical criteria. Group 2 consisted of 912 patients (85.9%) who met the criteria according to genetic variants. The mean ages at symptom onset in groups 1 and 2 were 5.6 +/- 3.8 and 1.5 +/- 1.2 years, respectively (p = 0.024). Whereas the mean annual attack frequency was 2.7 +/- 3.1/year in group 1, it was 4.1 +/- 2.3/year in group 2 (p = 0.04). The pathogenic variant was higher in the colchicine-resistant group compared with the responders (p = 0.12). Conclusions: The Eurofever/PRINTO classification criteria may provide a new perspective on the diagnosis and clinical follow-up of FMF patients. Patients with a pathogenic variant who meet the Eurofever/PRINTO classification criteria including genetic variables have earlier onset of disease and more frequent attacks than those who meet the criteria including clinical variables. These patients need regular and closer follow-ups in terms of attack frequency, colchicine dose adjustment, and colchicine resistance.