The Remarkable Characteristics of the Children with Colchicine-resistant Familial Mediterranean Fever in Turkey

Objectives: Colchicine is the fundamental treatment of familial Mediterranean fever (FMF). Still, 5-10% of patients are not in remission with colchicine treatment. A consensus could not be established for the definition of colchicine resistance in FMF. This study aimed to determine factors that help to predict colchicine resistance in pediatric FMF patients.

Methods: Patients with FMF that age of diagnosis was under 18 years old were included in our study. Fifty colchicine responsive and 33 colchicine-resistant patients were stratified as groups 1 and 2, respectively. Patients' clinical and laboratory findings were evaluated. Logistic regression analysis was used to determine the risk factors of colchicine-resistant FMF. Receiver operating characteristic (ROC) curve analysis was used to identify and compare the predictive performances of colchicine-resistant FMF models.

Results: Homozygous exon 10 MEFV mutations were frequent in group 2 (Group 1: 34 (68%), group 2: 32 (97%), p = .013). Univariate analysis showed that the age of onset of symptoms, age of diagnosis, chronic arthritis, myalgia and diarrhea during attacks, and the number of attacks, high ISSF and Pras score, high C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) values under colchicine treatment were risk factors for colchicine-resistant FMF. With multivariate analysis, the number of attacks (OR 1.418, CI (95%) 1.149-1.750, p = .001) and high ESR values (OR 1.129, CI (95%) 1.059-1.204, p<.001) were detected as independent risk factors for colchicine-resistant FMF.

Conclusion: The predictive factors were determined for pediatric colchicine-resistant FMF in our study. The results will help to early diagnosis and treatment of chronic inflammation in FMF.