Background Juvenile idiopathic arthritis (JIA) is one of the most common chronic diseases of childhood. Interstitial lung disease (ILD) have been recently reported in JIA patients with increased frequency. Diffucing capacity for carbon monoxide (DLCO) is a commonly performed and clinically useful pulmonary function test that provides a quantitative measure of gas transfer in the lungs; it is often abnormal in patients with ILD. It has been known that there is a relationship between the development of pulmonary disease and treatment with various drugs such as methotrexate (MTX).
Objectives The aim of this study is to evaluate total lung function and DLCO in JIA patients and to evaluate the relationship with disease activity and treatment.
Methods 26 Caucasian patients with JIA were recruited with a control group of 15 healthy children. A full history, physical examination, current laboratory tests and full lung function tests including DLCO were performed in patients and controls.
Results We found a reduction in DLCO values in JIA patients (mean 75%) versus controls (mean 100%, p=0.005). A sub-analysis demonstrated that the subgroup of patients on MTX had worse DLCO diffusion values compared to control group (mean 65% p=0.002). By contrast, the subgroup of JIA children taking other drugs did not present significant DLCO differences compared to controls. In addition, DLCO was significantly lower in patients with active disease compared to controls (mean 65% p=0.001), whereas no significant differences between patients with inactive disease and healthy controls was found.
Conclusions This study showed a significant impairment of pulmonary DLCO in patients with JIA compared to controls. The main alterations in DLCO have been found in patient treated with MTX and in those with active disease. Moreover, a negative correlation between MTX therapy length and DLCO values was demonstrated. Further studies including larger populations are needed to confirm these data.
Schmelling H, Stephan V, Burdach S, et al. Pulmonary Function in Children with Juvenile Idiopatic Arthritis and effects of Methotrexate Therapy. Z Rheumatol 2002. 61(2):168-72.
Knook LME, de Kleer IM, Van de Ent CK, et al. Lung Funcion abnormalities and respiratory muscle weakness in children with juvenile chronic arthiritis 1999. Eur Respir J. 14:529-533.
Disclosure of Interest None declared