Colchicine resistance prediction criteria from the TURPAID cohort do not apply to the JIR cohort: a multicentre descriptive analysis.

INTRODUCTION

Familial Mediterranean fever (FMF) is the most common monogenic autoinflammatory disease. Colchicine is the first-line treatment, yet 5-10% of patients are resistant, increasing the risk of complications like amyloidosis. In 2023, Batu et al proposed the Turkish Paediatric Autoinflammatory Diseases (TURPAID) score to predict colchicine resistance in paediatric FMF at diagnosis. Its utility in broader populations is unknown. We assessed its performance in paediatric and adult FMF patients from the international Juvenile Inflammatory Rheumatism (JIR) cohort.

METHODS

We retrospectively analysed 236 genetically confirmed FMF patients treated with colchicine for ≥6 months. Patients were classified as colchicine-sensitive (CoS) or colchicine-resistant (CoR) based on the initiation of biologic therapy, which served as an operational definition of resistance, and matched for age and sex. The TURPAID score (range 0-4; resistance threshold ≥2) was retrospectively applied. Receiver operating characteristic (ROC) curves were used to assess predictive value.

RESULTS

A TURPAID score ≥2 was observed in 89% of paediatric and 76% of adult CoS patients. Mean scores were significantly higher in paediatric-onset FMF. ROC analysis showed poor discrimination in both paediatric and adult groups (area under the curve=0.6). Clinical features and attack patterns varied by age. The genetic component (1.5 points for MEFV exon 10 mutations) contributed to overclassification, reducing predictive accuracy.

CONCLUSION

The TURPAID score did not effectively predict colchicine resistance in the JIR cohort. Its limited generalisability may stem from age-related differences, recall bias and excessive genetic weighting. Genetic results should be a prerequisite and not a determinant of colchicine resistance prediction scores in FMF.