Background Vocal cord dysfunction (VCD) is often initially misdiagnosed as, or may coexist with, asthma. Identifying the differences between the types of triggers for each condition may help differentiate between these two conditions, and could give mechanistic insights.
Aim The aim of this study is to identify and compare patient-reported triggers in VCD and asthma.
Methods This was a two-part study. Part A – A retrospective case note review of the triggers of VCD from endoscopically-confirmed VCD patients was conducted. This information was used to generate a Breathlessness Triggers Survey with triggers recorded under the categories: scents, environmental factors, temperature, emotions, mechanical factors and daily activities. Part B – A prospective study which involved patients with VCD and/or asthma completing the Breathlessness Triggers Survey, rating the likelihood of each item triggering their symptoms using a five-point Linkert scale (strongly disagree to strongly agree). Chi-square test was performed to compare responses by cohort.
Results Part A – Data from 202 patients with VCD (73.3% female, mean age 53.1yrs) were included in the retrospective study. The findings were used to create a 23-item Breathlessness Triggers Survey for Part B of the study. Part B – 38 patients with VCD-only (63.2% females, mean age 56.8 yrs), 39 patients with asthma-only (56.4% female, mean age 53.3 yrs) and 12 patients with both VCD and asthma (83.3% female, mean age, 56.8yrs) were recruited. The mean number of patient-reported triggers in the VCD and asthma cohort was 11 and 13 respectively. Mechanical factors such as talking (p ≤ 0.001), shouting (p = 0.004) and swallowing (p ≤ 0.001) were more common in the VCD cohort, whilst environmental factors such as pollen/flowers (p = 0.002) and damp air (p = 0.039) were more common in asthma. There were no differences between groups in frequency of reporting scents as triggers (except for vinegar, more common in VCD), temperature, emotions or daily activities.
Conclusion There were notable differences and overlaps between patient-reported triggers of VCD and asthma, which could give clues to diagnosis during clinical assessment. Future work should focus on the mechanisms underlying these findings.