Development and first validation of the COPD Assessment Test

Abstract

There is need for a validated short, simple instrument to quantify chronic obstructive pulmonary disease (COPD) impact in routine practice to aid health status assessment and communication between patient and physician. Current health-related quality of life questionnaires provide valid assessment of COPD, but are complex, which limits routine use.The aim of the present study was to develop a short validated patient-completed questionnaire, the COPD Assessment Test (CAT), assessing the impact of COPD on health status. 21 candidate items identified through qualitative research with COPD patients were used in three prospective international studies (Europe and the USA, n51,503). Psychometric and Rasch analyses identified eight items fitting a unidimensional model to form the CAT. Items were tested for differential functioning between countries. Internal consistency was excellent: Cronbach's a50.88. Test re-test in stable patients (n553) was very good (intra-class correlation coefficient 0.8). In the sample from the USA, the correlation with the COPD-specific version of the St George's Respiratory Questionnaire was r50.80. The difference between stable (n5229) and exacerbation patients (n567) was five units of the 40-point scale (12%; p,0.0001).The CAT is a short, simple questionnaire for assessing and monitoring COPD. It has good measurement properties, is sensitive to differences in state and should provide a valid, reliable and standardised measure of COPD health status with worldwide relevance.

Is the high intensity symptoms experienced by patients admitted with chronic obstructive pulmonary disease documented by health professionals? - a prospective survey with comparison of patient reported outcomes and medical records

“…CAT [28] was designed to reflect the impact of COPD on patients’ health status [30]. CAT was developed based on a population containing all degrees of COPD ( n  = 1503) [30].…”

“…CAT was developed based on a population containing all degrees of COPD ( n  = 1503) [30]. Through item response theory (IRT) eight items were identified each covering a symptom.…”

Validation of the COPD Assessment Test (CAT) in patients with idiopathic pulmonary fibrosis

“…Several validated tests are available for use with patients with COPD, a disease with symptoms that are similar to IPF. One of those is the COPD Assessment Test (CAT), which is a short instrument to quantify COPD’s impact in practice [20]. The CAT has previously been tested and shown good psychometric properties among patients with a mixed group of ILD [21] but has not been tested among patients diagnosed with IPF.…”

Factors influencing pharmacological treatment in COPD: a comparison of 2005 and 2014

“…Frequent exacerbations are still defined as two or more exacerbations or one hospitalized exacerbation during the previous year. Symptoms can be evaluated using the COPD Assessment Test (CAT) [2], Clinical COPD Questionnaire (CCQ) [3], or Modified Medical Research Council (mMRC) scale [4].

Figure 1.Treatment patterns 2005 and 2014.

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