Objectives To compare pulmonary function in patients with juvenile dermatomyositis (JDM) with that of matched controls; and to examine associations between pulmonary function impairment, high-resolution CT (HRCT) abnormalities and other disease variables in patients with JDM.
Methods A total of 59 patients with JDM clinically examined a median 16.8 years (range 2–38 years) after disease onset were compared with 59 age-matched and sex-matched controls. Pulmonary function tests included spirometry, diffusing capacity for carbon monoxide (DLCO) and body plethysmography. In patients with JDM, HRCT scans were performed and cumulative organ damage and patient-reported health status assessed.
Results Patients with JDM had lower total lung capacity (TLC) and DLCO compared to controls (p=0.003 and <0.001, respectively). A low TLC was found in 26% of patients versus 9% of controls (p=0.026), and a low DLCO in 49% of patients versus 9% of controls (p<0.001). HRCT abnormalities were found in 37% of patients, and included interstitial lung disease (ILD) (14%), chest wall calcinosis (14%) and airway disease (15%). Three patients were diagnosed as having ILD prior to the follow-up visit. A low TLC was more often found in patients with than without abnormal HRCT (50% vs 12%, p=0.002). HRCT abnormality correlated with cumulative organ damage (rs=0.346, p=0.008) and patient-reported health status at follow-up (p<0.005).
Conclusions Patients with JDM had smaller lung volumes than controls; a restrictive ventilatory defect was found in 26% and HRCT abnormality in 37% of the patients, and these findings were associated. Although mostly subclinical, the relatively high frequency of pulmonary involvement highlights the systemic nature of JDM.
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Funding The project received financial support form Dr Olga Imerslunds foundation, Oslo, Norway
Competing interests None.
Ethics approval This study was carried out in compliance with the declaration of Helsinki and was approved by the Regional Ethics Committee, (Helse Sør-Øst).
Provenance and peer review Not commissioned; externally peer reviewed.