title: Screening for connective tissue disease in pulmonary arterial hypertension.
abstract: OBJECTIVE
  To evaluate the utility of anti-nuclear antibody (ANA) levels in distinguishing the cause of pulmonary arterial hypertension as idiopathic (IPAH) or connective tissue disease related (CTD-PAH).
  
  
  METHODS
  We retrospectively identified patients with IPAH or CTD-PAH seen between 2010 and 2012 at our institution. Medical records were reviewed for demographic and clinical data and laboratory values.
  
  
  RESULTS
  Of 115 patients identified, 65 (56%) had IPAH and 50 (44%) had CTD-PAH. The mean age was 59 years and most of the patients (76%) were women. Most patients (64%) were in World Health Organization functional class III or IV. Compared with the IPAH group, the CTD-PAH group had significantly increased B-type natriuretic peptide levels (635 vs 325 pg/mL; P = 0.02) and decreased pulmonary vascular resistance (6 vs 9 WU; P = 0.04). The median ANA level was significantly higher in the CTD-PAH group than the IPAH group (7 vs 0 U; P < 0.001). The area under the receiver operating characteristic curve for a positive ANA to predict CTD-PAH was 0.91 (P < 0.001). A cutoff of 5 U for predicting ANA provided an optimal specificity of 94% and a sensitivity of 70%. The resulting likelihood ratio using the same cutoff was 12 (P < 0.001), or a positive predictive value of 91% with a negative predictive value of 79%.
  
  
  CONCLUSIONS
  In this selected cohort of patients, a quantitative ANA value >5 U may be useful in distinguishing CTD-PAH from IPAH, but a lower level does not confidently exclude CTD-PAH.
authors.affiliation: From the Department of Internal Medicine, Division of Pulmonary and Allergy Medicine, and Department of Critical Care, Mayo Clinic, Jacksonville, Florida.
authors.forename: Ricardo J
authors.initials: RJ
authors.lastname: Pagán
authors.affiliation: From the Department of Internal Medicine, Division of Pulmonary and Allergy Medicine, and Department of Critical Care, Mayo Clinic, Jacksonville, Florida.
authors.forename: Augustine S
authors.initials: AS
authors.lastname: Lee
authors.affiliation: From the Department of Internal Medicine, Division of Pulmonary and Allergy Medicine, and Department of Critical Care, Mayo Clinic, Jacksonville, Florida.
authors.forename: Christopher O
authors.initials: CO
authors.lastname: Austin
authors.affiliation: From the Department of Internal Medicine, Division of Pulmonary and Allergy Medicine, and Department of Critical Care, Mayo Clinic, Jacksonville, Florida.
authors.forename: Charles D
authors.initials: CD
authors.lastname: Burger
mesh_terms: D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D003240:Connective Tissue Diseases / Q000150:complications / Q000175:diagnosis* / Q000276:immunology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology* / Q000276:immunology; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies
chemical_list: D000974:Antibodies, Antinuclear; D015415:Biomarkers