title: A novel scoring system to distinguish vocal cord dysfunction from asthma.
abstract: BACKGROUND
  Vocal cord dysfunction is often misdiagnosed and mistreated as asthma, which can lead to increased and unnecessary medication use and increased health care utilization.
  
  
  OBJECTIVE
  To develop a valid scoring index that could help distinguish vocal cord dysfunction from asthma.
  
  
  METHODS
  We compared the demographics, comorbidities, clinical symptoms, and symptom triggers of subjects with vocal cord dysfunction (n = 89) and those with asthma (n = 59). By using multivariable logistic regression, we identified distinguishing features associated with vocal cord dysfunction, which were weighted and used to generate a novel score. The scoring index also was tested in an independent sample with documented vocal cord dysfunction (n = 72).
  
  
  RESULTS
  We identified symptoms of throat tightness and dysphonia, the absence of wheezing, and the presence of odors as a symptom trigger as key features of vocal cord dysfunction that distinguish it from asthma. We developed a weighted index based on these characteristics, the Pittsburgh Vocal Cord Dysfunction Index. By using a cutoff of ≥4, this index had good sensitivity (0.83) and specificity (0.95) for the diagnosis of vocal cord dysfunction. The scoring index also performed reasonably well in the independent convenience sample with laryngoscopy-proven vocal cord dysfunction and accurately made the diagnosis in 77.8% of subjects.
  
  
  CONCLUSIONS
  The Pittsburgh Vocal Cord Dysfunction Index is proposed as a simple, valid, and easy-to-use tool for diagnosing vocal cord dysfunction. If confirmed by a prospective evaluation in broader use, it may have significant clinical utility by facilitating a timely and accurate diagnosis of vocal cord dysfunction, thereby preventing misdiagnosis and mistreatment as asthma. Future prospective validation studies will need to be performed.
authors.affiliation: Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pa.
authors.forename: Russell S
authors.initials: RS
authors.lastname: Traister
authors.affiliation: Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pa.
authors.forename: Merritt L
authors.initials: ML
authors.lastname: Fajt
authors.affiliation: Division of General Internal Medicine, Department of Medicine, and Center for Research on Health Care Data Center, University of Pittsburgh, Pittsburgh, Pa.
authors.forename: Douglass
authors.initials: D
authors.lastname: Landsittel
authors.affiliation: Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pa. Electronic address: petrovaa@upmc.edu.
authors.forename: Andrej A
authors.initials: AA
authors.lastname: Petrov
mesh_terms: D000328:Adult; D001249:Asthma / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D016009:Chi-Square Distribution; D015897:Comorbidity; D003937:Diagnosis, Differential; D055154:Dysphonia / Q000453:epidemiology / Q000503:physiopathology; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D007828:Laryngoscopy; D016015:Logistic Models; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D009812:Odorants; D010414:Pennsylvania; D010614:Pharynx / Q000503:physiopathology; D010699:Phonation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012135:Respiratory Sounds / Q000503:physiopathology; D012307:Risk Factors; D064706:Vocal Cord Dysfunction / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D014827:Vocal Cords / Q000503:physiopathology*
keywords: ANOVA; Analysis of variance; Asthma; BMI; Body mass index; CI; Clinical scoring index; Confidence interval; GERD; Gastroesophageal reflux; IBS; IQR; Interquartile range; Irritable bowel syndrome; N/A; NPV; Negative predictive value; Not available; OR; Odds ratio; PPV; Positive predictive value; SOB; Shortness of breath; VCD; Vocal cord dysfunction