Pittsburgh Vocal Cord Dysfunction Index
Distinguishing vocal cord dysfunction fromasthma can be difficult. The Pittsburgh Vocal Cord Dysfunction Index is a clinical tool to help prevent the misdiagnosis and mistreatment of vocal cord dysfunction as asthma.
Research authors: Traister RS, Fajt ML, Landsittl D, and Petrov AA.
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Model ID
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MeSH terms
  • Asthma
  • Vocal Cord Dysfunction
  • Clinical Prediction Rule
  • Model type
    Linear model (Calculation)
    No Formula defined yet
    Condition Formula

    Additional information

    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 withlaryngoscopy-proven vocal cord dysfunction and accurately made the diagnosis in 77.8% of subjects.

    CONCLUSION: 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.

    SOURCE: Traister RS, Fajt ML, Landsittel D, Petrov AA. A novel scoring system to distinguish vocal cord dysfunction from asthma. J Allergy Clin Immunol Pract. 2014;2(1):65-9.

    Study Population

    Total population size: 148
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    Females: {{ model.numberOfFemales }}

    Categorical characteristics

    Name Subset / Group Nr. of patients
    Final diagnosis Vocal cord dysfunction 89
    Asthma 59
    Pittsburgh Vocal Cord Dysfunction Index
    Refer to Intended Use for instructions before use
    Evidencio B.V., Irenesingel 19, 7481 GJ, Haaksbergen, the Netherlands

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    Total index score:

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    Result interpretation

    In the underlying study performed by Traister et al. (2015) in 148 patients, a cutoff score of 4 gave a sensitivity of 83%, a specificity of 95%, a positive predictive value of 96%, and a negative predictive value of 77% and, given the balance of sensitivity and specificity, was determined to be the best cutoff for distinguishing VCD from asthma. By using prediction profiling, a cutoff score of 4 would give a 77% probability of having VCD.

    Traister RS, Fajt ML, Landsittel D, Petrov AA. A novel scoring system to distinguish vocal cord dysfunction from asthma. J Allergy Clin Immunol Pract. 2014;2(1):65-9.

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