PREDICT-crFMF Score: A Novel Model for Predicting Colchicine Resistance in Children with Familial Mediterranean Fever

OBJECTIVES:To develop a novel scoring system to predict colchicine resistance in Familial Mediterranean fever (FMF) based on the initial features of the patients.METHODS:The medical records of patients were analyzed prior to the initiation of colchicine. After generating a predictive score in the initial cohort, it was applied to an independent cohort for external validation of effectiveness and reliability.RESULTS:Among 1418 patients with FMF, 56 (3.9%) were colchicine resistant (cr) and 1312 (96.1%) were colchicine responsive. Recurrent arthritis (4 points), protracted febrile myalgia (8 points), erysipelas-like erythema (2 points), exertional leg pain (2 points), and carrying M694V homozygous mutation (4 points) were determined as the parameters for predicting cr-FMF in the logistic regression model. The cut-off value of 9 was 87% sensitive and 82% specific to foresee the risk of cr-FMF in the receiver operating characteristic. Validation of the scoring system with an independent group (cr-FMF = 107, colchicine responsive = 1935) revealed that the cut-off value was 82% sensitive and 79% specific to identify the risk of cr-FMF.CONCLUSIONS:By constructing this reliable and predictor tool, we enunciate that predicting cr-FMF at the initiation of the disease and interfering timely before the emergence of complications will be possible.