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* From the Department of Medicine, Walter Reed Army Medical Center, Washington, DC, and the Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD.
Correspondence to: Jeffrey Mikita, MD, Walter Reed Army Medical Center, Department of Medicine, Pulmonary Disease Services, 6900 Georgia Ave, NW, Washington, DC 20307; e-mail: jeffrey.a.mikita{at}us.army.mil
Abstract
Study objectives: To evaluate medical utilization by ambulatory patients with vocal cord dysfunction (VCD).
Design: Retrospective, case-control study.
Setting: Pulmonary disease clinic at an army tertiary-care center.
Patients: Twenty-five ambulatory patients with VCD (mean age, 41 years; range, 27 to 69 years) who were age- (± 3 years) and gender-matched to 25 control patients with moderate persistent asthma.
Measurements and results: Medical utilization for the year preceding the diagnosis of VCD or asthma was obtained from a computerized medical record. End points included total outpatient visits, evaluations by subspecialty physicians, presentations for urgent care, hospitalizations, and number of prescriptions. Total physician visits (477 visits vs 267 visits, respectively; p < 0.004) and subspecialty care visits (277 visits vs 118 visits; p < 0.007) were significantly greater among the VCD cohort as compared with the asthmatic cohort. The groups were also found to have comparable utilization of prescriptions (448 prescriptions vs 394 prescriptions, respectively; p < 0.63), frequency of hospitalizations (seven hospitalizations vs five hospitalizations; p < 0.59), and urgent care visits (45 visits vs 20 visits; p < 0.14).
Conclusions: Ambulatory VCD patients use significantly more medical provider resources and similar pharmaceutical assets as compared to patients with moderate persistent asthma.
Key Words: ambulatory care • asthma • dyspnea • vocal cords
Somatization has been postulated as a possible contributor to vocal cord dysfunction (VCD) ever since it was first termed Munchausen stridor in 1974.1 Patients with somatization disorders are known to consume large amounts of health-care assets.2 Similar findings have been demonstrated in a study3 of patients hospitalized for severe VCD; however, VCD is recognized to have a wide spectrum of disease manifestations and severity, and the utilization of medical resources by ambulatory patients with VCD is unknown.
The initial report of VCD1 describes a patient hospitalized 15 times for "nonorganic laryngeal obstruction," who improved with distraction and mild neck manipulation. Other early reports of VCD were also of severe respiratory dysfunction often leading to intubation or tracheostomy. Kellman and Leopold4 reported several VCD patients who improved after relaxation with techniques or medications, and suggested hysteria or conversion reaction as possible etiologies. A more recent investigation5 has revealed that VCD may present as a mimicker of asthma. Christopher et al6 further characterized five cases of respiratory distress diagnosed as "uncontrolled asthma," attributing them to "unusual glottic closure" during respiration. Extensive psychiatric evaluation of these patients showed that they were unaware of their upper airway obstruction. Furthermore, they were unable to consciously reproduce their VCD, leading to postulation that VCD may represent a learned and unconscious somatic expression of dysphoric feelings. Another study3 noted a great similarity in the presentation and medication regimens of patients hospitalized with VCD as compared to those with severe asthma. Also noteworthy is that over half of these patients were found to have concomitant asthma. And most recently, VCD has been shown to make up 15% of referrals for exertional dyspnea to a tertiary-care center.7
The only data on medical utilization by patients with VCD comes from Newman et al,3 who studied 95 patients admitted to the hospital with severe VCD and found that they averaged 9.7 emergency department visits and 5.9 hospitalizations over the year prior to presentation and diagnosis and had a 28% incidence of prior intubation. Furthermore, 34 of 42 patients who received a diagnosis of VCD in the absence of asthma were receiving oral steroids at the time of presentation at an average daily dose of 29.2 mg.
Ambulatory patients with VCD differ from those described by Newman et al.3 They have a more indolent presentation, with the majority complaining of dyspnea on exertion. These patients are rarely admitted to the hospital and frequently have comorbidities of gastroesophageal reflux disease or postnasal drip syndrome. Despite these relatively benign presentations, patients in our clinic with VCD are perceived to consume considerable medical resources. Given this perception and the linkage of VCD with somatization disorders, we postulate that medical utilization by ambulatory VCD patients is significant and possibly greater than that of a similar cohort of asthmatics, the disease group it is known to mimic.
Methods and Materials
We investigated all patients aged > 18 years old who underwent diagnostic laryngoscopy between January 2002 and February 2004 in the Pulmonary Disease Clinic at Walter Reed Army Medical Center. Diagnosis of VCD was made if laryngoscopy revealed inappropriate adduction of the true vocal cords during respiration as described by Wood and Milgrom.8 Subjects with VCD were then matched for age (± 3 years) and gender to control patients with moderate persistent asthma.9 The case control group was obtained by review of pulmonary function tests conducted in the same setting and timeframe. The diagnosis of asthma was made on clinical grounds and required objective criteria of reversible airway obstruction as defined by the American Thoracic Society.1011 VCD patients and their asthmatic matches were excluded if they lacked evidence of local enrollment in our health-care system throughout the year preceding their respective diagnosis. Data for the year antecedent the diagnosis were then collected from an electronic medical database. End points included the number of each of the following types of health-care evaluations: primary care, subspecialty, allergy, pulmonary, otolaryngology, cardiology, sick call, emergency department, and inpatient. Composite analysis of sick call and emergency department visits were defined as urgent care. Pharmacy utilization end points included total number of prescriptions and breakdown analyses of the following classes of medications: oral glucocorticoids, oral antibiotics, pulmonary inhalers, and gastroesophageal reflux, rhinitis, and psychiatric medications. Topical and ophthalmic preparations were excluded from analysis. Chart review was completed to further assess patient demographics and confirm the presence of histories consistent with diagnosis of VCD and asthma, respectively. Two-tailed t test analysis was utilized to compare differences between the two groups.
Two hundred thirty-nine patients underwent laryngoscopy. One hundred six of these patients received a diagnosis of VCD. Eighty-one patients were excluded, 53 because they were not locally enrolled and 28 because an appropriate asthmatic match could not be identified. Final enrollment included 25 VCD patients who were successfully matched to 25 asthmatic control subjects. Our investigational review board approved this protocol.
Results
The demographics and spirometry results for all subjects included in the study are depicted in Table 1 . Thirteen male and 12 female VCD patients with a mean age of 41 years (range, 27 to 69 years) met inclusion criteria and were successfully age- and gender-matched to asthmatic control patients. The two cohorts did not differ significantly with regard to smoking status and comorbidities of heart disease (n = 1 vs n = 2, respectively; p < 0.5), malignancy (n = 1 vs n = 1; p < 0.5), liver disease (n = 0 vs n = 1; p < 0.2), diabetes mellitus (n = 1 vs n = 0; p < 0.2), gastroesophageal reflux disease (n = 10 vs n = 6; p < 0.117), and chronic rhinitis (n = 12 vs n = 14; p < 0.290). However, only the VCD group included patients with lung disease other than asthma, with one patient each with COPD, sarcoidosis, and idiopathic pulmonary hemosiderosis. All of these diseases were quiescent during the study period by chart review. Interestingly, four of the VCD subjects (16%) had concomitant asthma. And as expected, the VCD and asthma cohorts differed by spirometry with regards to forced expiratory flow at 50% of FVC/forced inspiratory flow at 50% of FVC (FEF50/FIF50) [1.40 vs 0.59, respectively; p < 0.001] and FEV1/FVC (75.3 vs 66.0, respectively; p < 0.01). There was no difference in FVC and FEV1.
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Given our role in determining soldier fitness for duty, we have adopted an aggressive evaluation for the etiology of unexplained dyspnea. Patients typically are studied with routine spirometry before and after bronchodilator, followed by methacholine challenge and eucapnic voluntary hyperventilation bronchoprovocation tests, and finally cardiopulmonary exercise tests when indicated. Diagnostic laryngoscopy is performed if this evaluation does not yield a diagnosis and there is concern for VCD. As expected with this approach, nearly half of all laryngoscopy yielded an objective diagnosis of VCD.
The results of our study show that ambulatory patients with VCD use large amounts of medical resources. The frequency of subspecialty evaluations and number of pulmonary visits preceding their diagnosis supports the assertion that somatization may play a role in VCD. It also underscores the diagnostic challenge that these patients often present. Our patients with VCD had many similar attributes to those previously described in the literature such as concomitant asthma, elevated FEF50/FIF50, and oral glucocorticoid use. Also, these patients had considerable gastroesophageal reflux disease and chronic rhinitis. Medical utilization among VCD patients differed from the study by Newman et al,3 in that our population had relatively few hospitalizations and urgent-care visits. However, they did demonstrate high levels of outpatient visits and prescriptions as postulated. Interestingly, our study population was older and lacked a female predominance. This may reflect a population bias as the military has significantly more men, artifact as a result of exclusion criteria, or more even gender distribution of patients with ambulatory VCD as compared with those hospitalized for VCD. Our asthma cohort had expected spirometry results showing obstruction. Antibiotic and inhaler prescriptions were significantly greater in the asthmatics, which may reflect increased sputum production and a better response to inhalers as has been described previously,3 or it may reflect that providers recognize a difference in these patients or their symptoms. Furthermore, this may represent a higher threshold of providers to withhold oral steroids vs antibiotics or inhaler medications.
Our study may be limited by its retrospective nature and high exclusion rate. Although a prospective design would not likely have changed our findings as we believed, we captured all possible patients who would have met enrollment criteria. At our institution, the pulmonary clinic is the only physician service managing VCD, and all patients who are referred to speech therapy for VCD are evaluated in our clinic. Rigorous study criteria, transient patient population, and our status as a tertiary referral center for much of the military resulted in exclusion of approximately three fourths of the patients who received a diagnosis of VCD during the study period. This study population is likely different from our baseline in that it represents primarily dependents and retirees and not active duty military. This may have the impact of making our results more generalizable to the civilian community.
Conclusion
Ambulatory patients with undiagnosed VCD have significantly more physician and subspecialty care visits than patients with moderate persistent asthma, a group known to have high medical utilization. Frequent health-care visits and multiple prescriptions may be useful markers for suspected VCD as well as discriminators from asthmatics. Aggressive diagnosis and management of ambulatory VCD patients may have a significant impact on health-care utilization. Further investigation of diagnostic strategies, effective management, and postdiagnosis health-care utilization of VCD patients along with education of health-care providers is warranted.
Footnotes
Abbreviations: FEF50/FIF50 = forced expiratory flow at 50% of FVC/forced inspiratory flow at 50% of FVC; VCD = vocal cord dysfunction
This work was performed at Walter Reed Army Medical Center, Washington, DC.
Received for publication February 22, 2005. Accepted for publication June 16, 2005.
References
This article has been cited by other articles:
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  K. L. Christopher Understanding vocal cord dysfunction: a step in the right direction with a long road ahead. Chest, April 1, 2006; 129(4): 842 - 843. [Full Text] [PDF]
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