Reliability and validity of the self-administered Chinese version of the shortness of breath questionnaire (C-SOBQ) in patients with chronic obstructive pulmonary disease

Background: Dyspnoea is crucial in evaluating patients with chronic obstructive pulmonary disease (COPD). The San Diego Shortness of Breath Questionnaire (UCSD SOBQ) assesses shortness of breath in activities of daily living (ADL). It has been translated into Chinese and used clinically in Hong Kong for many years. Objective: To investigate the reliability and validity of a self-administered Chinese version of the Shortness of Breath Questionnaire (C-SOBQ) with pictorial enhancement in patients with COPD in Hong Kong. Methods: A total of 119 patients with COPD were recruited by convenience sampling from seven public clinical settings and two community self-help groups. The C-SOBQ score for each patient was correlated with a set of criterion parameters including age, body mass index (BMI), 6-minute walking distance (6MWD) test, lung function physiological parameters, BODE index, the Modified Medical Research Council Dyspnoea Scale (MMRC Dyspnoea Scale), and the Global Initiative for Chronic Obstructive Lung Disease (GOLD) COPD classifications. For test-retest reliability, 22 out of 119 patients were selected and assessed using the C-SOBQ followed by a reassessment within 1 week by the same rater. Results: The C-SOBQ shows good test-retest reliability with an intra-class correlation coefficient of 0.915 (p ≦ .05). It demonstrates significant correlations with the MMRC Dyspnoea Scale, GOLD COPD classifications, BODE index, BMI, and 6MWD. The BODE index, MMRC Dyspnoea Scale, and 6MWD were valid predictors of C-SOBQ total score. A total of 50.4% of patients could be correctly grouped in quartiles of the BODE index using the C-SOBQ. Conclusion: The C-SOBQ with pictorial enhancement is a valid and reliable instrument which gives precise information about the impact of dyspnoea on functional activities for patients with COPD.