Content Validity of CASA-Q Cough Domains and UCSD-SOBQ for Use in Patients with Idiopathic Pulmonary Fibrosis

Katharine Suzanne Gries,Ingela Wiklund,Dirk Esser

doi:10.5539/gjhs.v5n6p131

Abstract

Purpose:The study objective was to assess the content validity of the Cough and Sputum Assessment Questionnaire (CASA-Q) cough domains and the UCSD Shortness of Breath Questionnaire (SOBQ) for use in patients with Idiopathic Pulmonary Fibrosis (IPF).Methods:Cross-sectional, qualitative study with cognitive interviews in patients with IPF. Study outcomes included relevance, comprehension of item meaning, understanding of the instructions, recall period, response options, and concept saturation.Results:Interviews were conducted with 18 IPF patients. The mean age was 68.9 years (SD 11.9), 77.8% were male, and 88.9% were Caucasian. The intended meaning of the CASA-Q cough domain items was clearly understood by most of the participants (89–100%). All participants understood the CASA-Q instructions; the correct recall period was reported by 89% of the patients, and the response options were understood by 76%. The intended meaning of the UCSD-SOBQ items was relevant and clearly understood by all participants. Participants understood the instructions (83%) and all patients understood the response options (100%). The reported recall period varied based on the type of activity performed. No concepts were missing, suggesting that saturation was demonstrated for both measures.Conclusions:This study provides evidence for content validity for the CASA-Q cough domains and the UCSD-SOBQ for patients with IPF. Items of both questionnaires were understood and perceived as relevant to measure the key symptoms of IPF. The results of this study support the use of these instruments in IPF clinical trials as well as further studies of their psychometric properties.

Highlights

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, debilitating fibrotic lung disease, of unknown origin, which is the most common of the idiopathic interstitial pneumonias (Raghu et al, 2011)
Interviews were conducted with 18 Idiopathic Pulmonary Fibrosis (IPF) patients
All participants understood the Cough and Sputum Assessment Questionnaire (CASA-Q) instructions; the correct recall period was reported by 89% of the patients, and the response options were understood by 76%

Summary

Introduction

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, debilitating fibrotic lung disease, of unknown origin, which is the most common of the idiopathic interstitial pneumonias (Raghu et al, 2011). Patients with IPF have substantial impairment in health-related quality of life (HRQoL), in the domains of physical health and level of independence, and a number of patient reported outcome (PRO) tools have become available to measure this impairment (Swigris, Kuschner, Jacobs, Wilson, & Gould, 2005). The St. George’s Respiratory Questionnaire (SGRQ), originally developed for use with patients with COPD, has been adapted for assessment in IPF (as SGRQ-I), and more recently, an IPF-specific HRQoL instrument, the ATAQ-IPF (A Tool to Assess QOL in IPF), and an interstitial lung disease (ILD)-specific HRQoL instrument, the King’s Brief Interstitial Lung Disease (K-BILD) have been developed

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