Effect of biologic treatments on growth in children with juvenile idiopathic arthritis.

Objective: Growth retardation is a frequent complication of severe juvenile idiopathic arthritis (JIA). Biologic treatments may improve growth velocity by controlling systemic inflammation and reducing corticosteroids. Our goals were to compare growth velocity before and after the onset of biologic therapy and to determine whether the JIA subtype, the use of steroids, the requirement of one or several biologic agents, or the disease activity influenced growth velocity.

Methods: We retrospectively analyzed the growth of children with JIA who never received growth hormone treatment, who started biologic treatment before puberty, and who were followed for at least 6 months afterward.

Results: We included 100 children (33 boys). Median patient age was 7.1 years (range: 1.6-15.7) at the onset of biologic treatment and 11.0 years (range: 2.3-19.5) at the latest followup. Forty-six patients had received corticosteroid and 34 had received more than 1 biologic agent. Patient median height expressed as SD score (SDS) was 0.31 (range: -2.47 to 5.46) at disease onset, -0.24 (-3.63 to 2.90) at biologic therapy onset (p < 0.0001), and -0.15 (-4.95 to 3.52) at the latest followup (p = 0.171 compared to biologic treatment onset). Patients who required several biologics and systemic patients had a significantly lower growth velocity after the onset of biologic treatment. At the latest followup, 18% of our study group had low growth velocities and 19% were below -2SD or shorter than genetically programmed.

Conclusion: In a subset of patients, particularly systemic JIA patients and patients who required more than 1 biologic, biologic therapy may be insufficient to restore normal growth velocity.