In patients with juvenile idiopathic arthritis (JIA), treatment with methotrexate (MTX) as the sole disease-modifying antirheumatic drug (DMARD) often results in the achievement of inactive disease (ID), according to study results published in Pediatric Rheumatology.

The study included patients with JIA who started MTX as the sole DMARD (n=375) between 2000 and 2013. The researchers reviewed patients’ clinical charts. Follow-up was ended at the first episode of ID; for patients who did not reach ID, the last follow-up or the visit at which a biologic agent was prescribed was used. The state of ID was defined by the Wallace criteria.

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Using univariate and multivariate analyses, the researchers compared the characteristics at the start of MTX of patients who achieved ID with patients who did not achieve ID. They used regression coefficients of variables that entered the best-fitting logistic regression model to determine a prediction score for lack of achievement of ID.

During MTX administration, 8.8% of patients were given systemic corticosteroids and 44.1% were given intra-articular corticosteroids.

Of 375 patients, 61% (n=229) achieved ID after a median of 1.7 years, while 39% (n=146) did not achieve ID after a median of 1.2 years.

After performing a multivariate analysis, the researchers found that systemic arthritis, enthesitis-related arthritis (ERA), polyarthritis and C-reactive protein (CRP) >1.4 mg/dL had independent correlations with nonachievement of ID.

Prediction scores ranged from 0 to 3. The researchers determined that the cutoff that most effectively separated patients who did or did not achieve ID was >0.5. Systemic arthritis and ERA both had scores >0.5 and predicted a lower likelihood of achieving ID. Polyarthritis and increased CRP had a score of 0.5 and only predicted a reduced likelihood of achieving ID in association with other variables.

“These findings help to outline the characteristics of JIA patients who may deserve the prescription of a synthetic DMARD other than MTX or the introduction of a biologic DMARD from the disease outset,” the researchers wrote.

Reference

Bava C, Mongelli F, Pistorio A, et al. A prediction rule for lack of achievement of inactive disease with methotrexate as the sole disease-modifying antirheumatic therapy in juvenile idiopathic arthritis. Pediatr Rheumatol. 2019;17:50.