PURPOSE:Chronic persistent cough is a frustrating and bothersome symptom for many adults, making it an important target for new therapies. The purpose of this study was to evaluate how cough is described and measured in the published literature, understand the patient’s perspective of this symptom, and develop a framework of cough severity to inform the development of a new patient-reported outcome (PRO) measure for use in clinical trials.
METHODS:A comprehensive literature review was performed using PubMed and Embase (2002–2006). Patients with a medically-confirmed chronic cough participated in one of three focus groups. An experienced discussion leader followed a semi-structured interview format to elicit information about how patients describe and characterize cough severity. Audiotapes were transcribed and qualitative data were analyzed to identify central themes, phrases and words patients use to describe cough severity.
RESULTS:The literature review uncovered 18 relevant papers published in English describing cough and various approaches to measurement. Cough severity was frequently assessed with single-item measures using 100mm visual analog or 10-point scales; however no validated PRO instruments to assess cough severity were identified. Twenty-two patients participated in focus groups; mean age = 66 (+ 13) years; 16 (73%) female; most (n=18) had cough duration of greater than one year. Participants described cough severity in terms of frequency (cough, urge, and “bouts”), intensity (harshness, discomfort) and disruptiveness (daytime and nighttime). Some patients coughed frequently but without intensity while others described frequent, intense, and debilitating coughing “fits” or “bouts.” All patients described day-to-day variability of this symptom.
CONCLUSION:There is no validated tool to capture patient report of cough severity in clinical trials, making cross-study comparisons and conclusions regarding treatment efficacy difficult.
CLINICAL IMPLICATIONS:Results of the literature review and focus groups suggest a comprehensive patient-reported cough severity tool should include items addressing frequency, intensity and disruptiveness rated on a 10-point or VAS-type scale and administered on a daily basis.
DISCLOSURE:Linda Nelsen, Employee Merck & Co., Inc.; No Product/Research Disclosure Information