Behçet's disease‬ and familial Mediterranean fever: Two sides of the same coin or just an association? A cross-sectional study‬.

BACKGROUND

Familial Mediterranean fever (FMF) is a genetic disease, characterized by attacks of fever, arthritis, serositis and pain. Behçet's disease (BD) is an inflammatory disorder with a genetic basis, characterized by oral and genital ulcers, uveitis, pustular erythematous cutaneous lesions, arthritis, central nervous system involvement and possible vascular manifestations such as venous thrombosis, arteritis and aneurysms.

OBJECTIVES

To investigate the association and actual differentiation between these two entities in a large-scale population-based study.

METHODS

Data for this study was collected from the databases of "Clalit Health Services", the largest state-mandated health service organization in Israel. All adult members diagnosed with BD were included (n=892) and as well as their age- and sex-matched controls (n=4444), creating a cross-sectional population-based study. Medical records of all subjects were analyzed for documented FMF. A logistic regression model was done to estimate how BD, age, gender, BMI, ethnicity and socioeconomic status contributed as risk factors for FMF.

RESULTS

The proportion of FMF in patients with BD increased compared with those reported in controls (5.83% and 0.23%, respectively, P<0.001). This coexistence was prominent among both sex groups but was much stronger among female BD patients (females with OR of 177 and of 8.4 in males, P<0.001). In a multivariate analysis, BD was identified as an independent risk factor for FMF (OR 25.16, 95% CI 13-53.3).

CONCLUSION

BD diagnosis was found to be independently associated with higher incidence of FMF, especially in females, people of Arab descent and BMI>30. Our data imply that understating the differentiation between FMF and BD is not evident and clear in a real-life population of patients with BD.