Growth and body mass index in a cohort of patients with juvenile idiopathic arthritis: effects of second line treatments.

Objective Juvenile idiopathic arthritis (JIA) may affect natural growth. The aim of the study has been to assess auxological parameters of JIA patients, receiving different anti-rheumatic treatments. Methods This is a retrospective study; JIA patients were recruited from the Rheumatology Unit of Anna Meyer Children's University Hospital of Florence, Italy from March 1996 to June 2016. Results Two hundred and thirty-two patients were included in the current study. The best result in terms of catch-up growth occurred in systemic JIA patients. All JIA categories showed standard deviation score (SDS) gain for height except those belonging to enthesitis related arthritis category. Patients treated with disease-modifying anti-rheumatic drugs (DMARDs) only maintained constant growth during study follow-up. Patients who needed biologic therapy showed an impaired growth during pre-DMARDs treatment and an increased growth velocity mostly during biologic therapy. Body mass index (BMI) decreased in almost all JIA categories. The best BMI reduction was observed among patient receiving biologic drugs. Conclusion Patients with JIA followed in our centre had a gain of height SDS and lost BMI SDS in 5 years of follow-up. We observed a stable and good pattern of growth in patients treated with DMARDs and an increased growth velocity during biologic treatment.