Clustering Chronic Cough Patients Using Reported Sensations and Triggers, Results from the TOPIC Questionnaire

Background: Chronic cough (CC) is one of the commonest presentations to primary care and to respiratory outpatient clinics 1-4. The Triggers and Sensations Provoking Coughing (TOPIC) questionnaire is a 15-item questionnaire designed to capture sensations and triggers associated with CC in a fashion that discriminates between Refractory Chronic Cough (RCC) and other causes of CC.<br/>Research Questions: Is there a relationship between TOPIC scores and other measures of cough in patients referred to three specialist cough clinics? Can patients with CC be clustered based on reported sensations and triggers as captured by the TOPIC questionnaire? <br/>Study Design and Methods: This was a multi-centre observational study. Data was collected including: Leicester Cough Questionnaire (LCQ) score, verbal cough severity, day and night cough VAS, 24-hour cough frequency and TOPIC questionnaire results. Patterns of TOPIC responses were explored using cluster analysis.<br/>Results: Baseline data was collected on 101 participants. Demographics of study participants were typical of CC patients; 65% female with a mean (SD) age of 59 (+/- 12.9) years. Baseline TOPIC score correlated moderately negatively with baseline LCQ score (r=-0.59, p&lt;0.001) but not with other subjective or objective measures of cough. Hierarchical and K mean cluster analysis were used to group study participants into 4 distinct clusters based on triggers and sensations of cough as captured by the TOPIC questionnaire: i) “high sensations burden”; ii) “vocal triggers”; iii) “eating triggers”; and iv) “need to throat clear”. These groups showed statistically significant differences in their demographics and subjective measures of cough (p&lt;0.01).<br/>Interpretation: Patients with CC reported unpleasant somatic sensations and cough triggers captured by the TOPIC questionnaire, associated with lower LCQ scores and worse Quality of Life (QOL). TOPIC questionnaire responses can be used to cluster patients into clinical phenotypes based on reported sensations and triggers.