Original article
Development of the Japanese version of the COPD Assessment Test

https://doi.org/10.1016/j.resinv.2012.05.003Get rights and content

Abstract

Background

We aimed to develop the Japanese version of the COPD Assessment TestTM (CAT), which was recently developed in overseas countries, to measure the health status of patients with chronic obstructive pulmonary disease (COPD) and to validate its psychometric properties.

Methods

The original CAT was translated to Japanese through linguistic validation. Then, an Internet-based survey was conducted by including 301 Japanese patients with COPD who were over 40 years of age and had a history of smoking, to assess the reliability and validity of the translated CAT.

Results

The Japanese CAT was shown to have high internal consistency (Cronbach's α coefficient: 0.891). The assessment using the Japanese CAT was highly correlated with assessment using the COPD-specific St. George's Respiratory Questionnaire (r=0.820). The assessment also showed correlation between the Japanese CAT and a generic health-related quality of life (QOL) questionnaire (SF-12v2).

Conclusion

The Japanese version of the CAT has high reliability and validity, and can be expected to serve as a short and simple questionnaire for precise assessment of the health status of Japanese patients with COPD.

Introduction

Chronic obstructive pulmonary disease (COPD) is an inflammatory disease of the lung primarily caused by smoking. It is a progressive disease that is associated with progressive deterioration of respiratory function and eventual restriction of activities of daily living. COPD is the ninth leading cause of mortality in Japan (2010) and the number of COPD-related mortalities has tended to steadily increase in recent years [1]. According to the Guidelines for the Diagnosis and Treatment of COPD (Chronic Obstructive Pulmonary Disease) established by The Japanese Respiratory Society [2] and The Global Initiative for Chronic Obstructive Lung Disease [3], COPD should be considered a systemic disease rather than as a localized lung disease, because it is frequently associated with systemic inflammation, cardiovascular diseases, depression, and diabetes. Furthermore, a large telephone survey conducted in Japan has shown that activities of daily living in Japanese patients with COPD are restricted in many ways, and that the majority of these patients have not yet been diagnosed or appropriately treated [4]. These findings highlighted the urgent need for improvements in COPD diagnosis and management in general practice. Understanding the quality of life (QOL) of patients with COPD in daily clinical practice is important for appropriate management of COPD.

Tools developed for the assessment of the health-related QOL (HRQOL) in COPD patients include the St. George's Respiratory Questionnaire (SGRQ) [5] and the Chronic Respiratory Disease Questionnaire (CRQ) [6]. However, these instruments are not suitable for routine use in the management of patients with COPD in general practice, because they are too lengthy and the scoring algorithms are too complex. Therefore, Jones et al. developed a more concise tool that is easier to use, the COPD Assessment TestTM (CAT) [7]. The CAT is composed of items pertaining to 8 symptoms related to respiratory disorders: cough, phlegm, chest tightness, breathlessness, activity limitation at home, confidence in leaving home (mental), sleep, and energy (vigor). Patients are asked to respond to all items using an identical 0–5 response scale. The total score, ranging from 0 to 40, represents the health status of each respondent with COPD (the higher the score, the worse their health status). The CAT is intended to improve communication between the clinician and the patient, thus enabling a common understanding of the severity and impact of the patient's disease and allowing for better targeted treatment and optimized management of COPD. However, it is neither a diagnostic tool nor an alternative to lung function tests, such as spirometry.

In the present study, we report our development of a Japanese version of the CAT, a new COPD-specific questionnaire developed in overseas countries. We also evaluated whether the finalized Japanese version of the CAT can accurately describe the health status of Japanese patients with COPD.

Section snippets

Material and methods

The present study consisted of 2 steps. The first was linguistic validation, which involved translation of the original CAT to Japanese and adaptation to Japanese culture. The second was psychometric evaluation to statistically analyze the validity and reliability of the translated questionnaire in the target population.

In the linguistic validation step, translation of the questionnaire was undertaken by TransPerfect Translations, Inc. (New York, USA). A pilot test of the Japanese version of

Linguistic validation

In the medical review of the Japanese Version 1 of the CAT, the plainest Japanese expressions were selected, so that every respondent could understand the text of the questionnaire. In the pilot test using the revised Japanese translation of the CAT based on the review results (Japanese Version 2), all the respondents (3 males and 2 females with a mean age of 68.8 years) completed the questionnaire without missing data in an average of 3.2 min. When the comprehensibility of the questionnaire was

Discussion

As described above, we developed a Japanese version of the CAT, a new COPD-specific questionnaire developed in overseas countries. We also validated whether the finalized Japanese version of the CAT could accurately describe the health status of Japanese patients with COPD.

Linguistic validation, which was used to develop the Japanese CAT, is an approach widely recognized outside Japan. The objectives of linguistic validation are translation and adaptation to Japanese culture. The pilot test

Conflict of interest

Ichiro Arakawa serves as a consultant to GlaxoSmithKline K.K.

Division of Respirology, Neurology, and Rheumatology, Department of Medicine (1), Kurume University School of Medicine (Representative: Tomoaki Hoshino) received a research grant from Novartis Pharma K.K.; received Subsidies or Donations from GlaxoSmithKline K.K.

Tohru Tsuda, Rika Suematsu, Kumie Kamohara, Mariko Kurose, Ryusuke Tomioka, Tomotaka Kawayama, they have no potential conflict of interest..

Acknowledgment

The preliminarily results of the present study were reported at the 50th Annual Meeting of the Japanese Respiratory Society (Tokyo, April 2010) by the late Prof. Hisamichi Aizawa, Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine. The late Prof. Aizawa was involved at study conception, execution, and interpretation. The authors express their sincere gratitude to the late Prof. Aizawa for his invaluable contribution to the study.

References (12)

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Faculty of Pharmaceutical Sciences, Teikyo Heisei University, 4-1 Uruido-minami Ichihara, Chiba 290-0193, Japan. I. Arakawa is currently a consultant to GlaxoSmithKline K.K.

Deceased.

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