title: Influence of autoimmune biomarkers on interstitial lung diseases: A tertiary referral center based case-control study.
abstract: BACKGROUND
  The benefit of routinely measuring autoimmune biomarkers to evaluate patients with interstitial lung disease (ILD) remains debated outside specific contexts such as connective tissue disease (CTD). This study aimed at evaluating the influence of biomarkers on outcome on patients with ILD in a case-control study at a tertiary referral center. We hypothesized that patients with positive autoimmune biomarkers have increased odds of developing ILD even in the absence of CTD.
  
  
  METHODS
  We reviewed the medical records of 3573 patients seen at the ILD clinic in Mayo Clinic Rochester between September 2001 and September 2006. We assessed their clinical course through June 25, 2013. We included patients with patterns of ILD most often associated with CTD (n = 1256) while excluding patients with other known causes of ILD. Controls (n = 2317) included cases seen at the ILD clinic without evidence of ILD.
  
  
  RESULTS
  We identified 930 (26%) cases of ILD alone, 124 (3%) CTD alone, 326 (9%) ILD combined with CTD, and 2193 (61%) with no ILD or CTD. Positive antinuclear antibodies (ANA), rheumatoid factor and aldolase were associated with ILD. After adjustment for age, gender, race, smoking history and CTD, ANA remained an independent risk factor for ILD (OR 1.70, 95% CI 1.33-2.17). Among patients with ILD, the presence of CTD but not biomarker alone was associated with a better survival.
  
  
  CONCLUSIONS
  In this study, the presence of positive biomarkers was associated with increased odds of ILD, even in the absence of overt CTD, but was not associated with a better outcome.
authors: Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN, USA. Electronic address: bauer.philippe@mayo.edu.
authors: Philippe R
authors: PR
authors: Bauer
authors: Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN, USA. Electronic address: kalra.sanjay@mayo.edu.
authors: Sanjay
authors: S
authors: Kalra
authors: Rheumatology, Mayo Clinic, Rochester, MN, USA. Electronic address: osborn.thomas@mayo.edu.
authors: Thomas G
authors: TG
authors: Osborn
authors: Health Sciences Research - Epidemiology, Mayo Clinic, Rochester, MN, USA. Electronic address: stsauver.jennifer@mayo.edu.
authors: Jennifer
authors: J
authors: St Sauver
authors: Health Sciences Research - Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA. Electronic address: hanson.andrew@mayo.edu.
authors: Andrew C
authors: AC
authors: Hanson
authors: Health Sciences Research - Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA. Electronic address: schroedd@mayo.edu.
authors: Darrell R
authors: DR
authors: Schroeder
authors: Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN, USA. Electronic address: ryu.jay@mayo.edu.
authors: Jay H
authors: JH
authors: Ryu
mesh_terms: D000368:Aged; D000974:Antibodies, Antinuclear / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D005634:Fructose-Bisphosphate Aldolase / Q000097:blood; D006801:Humans; D007155:Immunologic Factors / Q000097:blood*; D053208:Kaplan-Meier Estimate; D017563:Lung Diseases, Interstitial / Q000097:blood / Q000175:diagnosis* / Q000209:etiology / Q000276:immunology* / Q000401:mortality; D008297:Male; D016347:Medical Records Systems, Computerized; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012217:Rheumatoid Factor / Q000097:blood*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012907:Smoking / Q000009:adverse effects; D062606:Tertiary Care Centers; D014481:United States
chemical_list: D000974:Antibodies, Antinuclear; D015415:Biomarkers; D007155:Immunologic Factors; D012217:Rheumatoid Factor; D005634:Fructose-Bisphosphate Aldolase
keywords: Antinuclear antibodies; Biomarkers; Case-control study; Connective tissue disease; Interstitial lung disease