On the definition of chronic cough and current treatment pathways: an international qualitative study

Abstract

Background: The pathogenesis of chronic cough is not well understood and treatment options are limited. In this study we sought to explore the current understanding and management of chronic cough across an international group of specialists.

Methods: This was an international study of cross sectional qualitative design. In depth interviews were carried out with "Respiratory Specialists" experienced in treating treating Chronic Obstructive Pulmonary Disease (COPD), idiopathic pulmonary fibrosis (IPF), idiopathic chronic cough (ICC) and/or lung cancer patients and with "Disease Experts" in the field of Chronic Cough. Participants in the study were recruited from the USA, UK, Germany, Ireland, Australia and Japan. Interviews with specialists were held at research facilities and with DEs over the telephone. These were preceded by the specialists completing case records of patients recently seen. All interviews were conducted by native speaking trained moderators using a semi-structured interview guide script. This was designed to elicit the definition of chronic cough, explore the unmet needs for each disease state, define therapy goals, identify patient phenotypes and give an overview of the treatment pathway.

Results: 76 specialists and 10 experts took part in the study. Over two thirds (70%) of respondents defined chronic cough as "cough lasting more than 8/12 weeks" (range 2 weeks to 2 years). Physicians emphasised three interdependent aspects of clinical assessment: impact on quality of life, type of cough (productive versus non-productive) and the underlying pathology. Specialists emphasised treating the underlying cause rather than the cough, this being most prominent in Japan. Experts as a group focussed on chronic cough independently. Evaluation of the respiratory system, GI tract and upper airway (ENT) for establishing an underlying cause was recommended. Type of cough (productive vs non-productive) and impact on quality of life influenced treatment initiation. 33% of patients with ICC were prescribed anti-tussives. With associated diagnoses of COPD, IPF or lung cancer the emphasis was on treating the underlying condition. Alternatives to pharmacological treatments were frequently considered.

Conclusion: There is significant international variation in our understanding and management of chronic cough. Further work is required to bring forth clear guidance and effective medicines for these patients.

Keywords: Chronic cough; Definition; Management; Qualitative research.

Figure 1

The structure and flow of the interview process.

Figure 2

Percentage of chronic cough case load ascribed to the different diagnoses is shown on the Y axis. Self-completion form allowed for ‘other’ category and hence total does not sum to 100%.

Figure 3

This figure demonstrates the nature of cough, dry or productive, as a percentage in patients with COPD, lung cancer, idiopathic pulmonary fibrosis and idiopathic chronic cough. Data was obtained from review of completed the patient case records.

Figure 4

Physicians timescale of definition of chronic cough.

Figure 5

Perception of impact on quality of life of the various conditions causing cough.

Figure 6

The various diagnoses spontaneously reported by respiratory specialists as cause for chronic cough in their patients is shown. The size script is weighted to reflect the frequency reported.