Fran Lowry

November 12, 2012

ANAHEIM, California — Younger age, shortness of breath, and stridor are strong predictors of vocal cord dysfunction, researchers reported here at the American College of Allergy, Asthma & Immunology 2012 Annual Scientific Meeting.

If the predictive value of these factors is confirmed in a larger population, it could help direct a clinician's decision to refer a patient for stroboscopic evaluation to confirm the diagnosis, said senior researcher Jonathan A. Bernstein, MD, professor of medicine at the University of Cincinnati in Ohio.

In the United States, "it is estimated that the prevalence of vocal cord dysfunction is about 10% to 15%. Among people diagnosed with asthma, probably 3% to 5% have the disorder," Dr. Bernstein told Medscape Medical News.

"The purpose of our study was to determine if we could find clinical characteristics that would be more predictive of a diagnosis of vocal cord dysfunction...because it would help clinicians decide when to refer," he said.

Vocal cord dysfunction is underrecognized, underdiagnosed, and can complicate the management of patients with asthma, Dr. Bernstein explained.

A stroboscopic examination can be difficult for some patients, especially because of the added expense, he continued.

In their study, Dr. Bernstein and colleagues conducted a retrospective chart review of 55 patients with suspected vocal cord dysfunction who were referred to a voice specialty center for stroboscopic evaluation. Their aim was to confirm or exclude the diagnosis.

The mean age of the men was 39 years (range, 33 to 44 years) and of the women was 34 years (range, 18 to 49 years). Although there were more women in the study than men (82% vs 18%), the researchers state in their abstract that "there was no significant difference between [women and men] with respect to a definitive or probable diagnosis of [vocal cord dysfunction]" (56% vs 70%).

Presenting symptoms included shortness of breath, stridor, wheezing, cough, throat pain, throat tightness, hoarseness, and exercise-induced asthma. Stroboscopic examination confirmed a definitive or probable diagnosis of vocal cord dysfunction in 58% (n = 32) of the patients.

On multivariate analysis, shortness of breath, stridor, and being younger than 38 years were found to be significant predictors of a diagnosis of vocal cord dysfunction (P < .05 for all).

"In this population, a younger-aged patient presenting with shortness of breath and stridor had a 17 times greater odds of having a positive diagnosis of vocal cord dysfunction" (< .001), Dr. Bernstein said.

"However, we will have to do longitudinal studies in larger populations to confirm this," he added.

According to John Oppenheimer, MD, clinical professor of medicine at the New Jersey Medical School in Newark, vocal cord dysfunction can be very bothersome and often is misdiagnosed as asthma.

"Vocal cord dysfunction is a masquerade of asthma. Some people can be so debilitated that they end up being treated as though they have horribly severe disease. They can be put on medicines that have a lot of side effects, such as prednisone, Dr. Oppenheimer, who was not involved in the study, told Medscape Medical News. Being able to distinguish who has vocal cord dysfunction and who does not is very helpful, he added.

"I think this study is important because it gets clinicians to start to think about the differential of wheezing and asthma and to try to determine what may be better indicators of this asthma-like illness," Dr. Oppenheimer said. He acknowledges that larger studies are needed.

Dr. Bernstein reports being medical director of Flint Hills Resources. Dr. Oppenheimer reports financial relationships with GlaxoSmithKline, Merck, AstraZeneca, Boehringer Ingelheim, MedImmune, and Novartis.

American College of Allergy, Asthma & Immunology (ACAAI) 2012 Annual Scientific Meeting: Abstract 31. Presented November 11, 2012.