Clinical and lung-function variables associated with vocal cord dysfunction

Area of Science:

• Pulmonology
• Respiratory Medicine
• Diagnostic Medicine

Background:

• Vocal cord dysfunction (VCD) presents diagnostic challenges.
• Laryngoscopy during symptomatic periods is the gold standard for VCD diagnosis.
• Identifying predictive clinical and spirometric variables for VCD is crucial.

Purpose of the Study:

• To identify clinical and spirometric variables that can predict the presence of VCD.
• To evaluate the utility of spirometry and flow-volume loops in diagnosing VCD.
• To determine predictors of VCD through multivariate logistic regression.

Main Methods:

• Two parallel studies were conducted, including pulmonologist assessment of flow-volume loops and a cross-sectional study of clinical/spirometric data.
• Pulmonologists evaluated flow-volume loops for VCD likelihood, blinded to laryngoscopy results.
• Multivariate logistic regression analyzed laryngoscopy findings against clinical characteristics and spirometry.

Main Results:

• Pulmonologist agreement on VCD prediction from flow-volume loops was moderate but not predictive of laryngoscopic diagnosis.
• VCD was diagnosed in 44% of 226 patients undergoing laryngoscopy.
• Independent predictors of VCD included female sex (OR 2.72) and obesity (OR 2.06).
• The ratio of forced inspiratory flow at 25% to 75% of inspired volume (FIF(25%/75%)) showed some predictive value (OR 1.97), but overall diagnostic performance was poor (AUC 0.68).
• No spirometric variables predicted VCD when controlling for inspiratory curve reproducibility.

Conclusions:

• Vocal cord dysfunction (VCD) remains difficult to predict using spirometry or flow-volume loops.
• Normal flow-volume loop patterns should not deter laryngoscopy if VCD is suspected.