title: Pulmonary outcome in juvenile dermatomyositis: a case-control study.
abstract: OBJECTIVE
  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 (r(s)=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.
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway. helga.sanner@medisin.uio.no
authors.forename: Helga
authors.initials: H
authors.lastname: Sanner
authors.forename: Trond Mogens
authors.initials: TM
authors.lastname: Aaløkken
authors.forename: Jan Tore
authors.initials: JT
authors.lastname: Gran
authors.forename: Ivar
authors.initials: I
authors.lastname: Sjaastad
authors.forename: Bjørn
authors.initials: B
authors.lastname: Johansen
authors.forename: Berit
authors.initials: B
authors.lastname: Flatø
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003882:Dermatomyositis / Q000150:complications* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D008297:Male; D011379:Prognosis; D011653:Pulmonary Diffusing Capacity; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed; D014109:Total Lung Capacity; D055815:Young Adult