Associations between the distance covered in the incremental shuttle walk test and lung function and health status in patients with chronic obstructive pulmonary disease.

BACKGROUND

Field walk tests such as the incremental shuttle walk test (ISWT) are simple tests for assessing the degree of disability in individuals with chronic obstructive pulmonary disease (COPD). In the present study, the correlations between exercise performance in the ISWT, lung function, and health status were examined in patients with COPD of varying severities.

METHODS

A retrospective examination of 277 COPD patients was performed using the ISWT and lung function tests along with assessment of health status using St. George׳s Respiratory Questionnaire (SGRQ). In addition, we assessed the correlations between the walking distance, lung function parameters, and SGRQ scores.

RESULTS

ISWT distances were poorly correlated with lung function parameters and SGRQ scores in mild COPD patients. In contrast, ISWT distances were significantly correlated with pulmonary function parameters, such as vital capacity (%predicted) and forced expiratory volume in one second, and SGRQ scores in moderate and severe COPD patients.

CONCLUSIONS

The ISWT is more independent of health status and pulmonary function in patients with mild COPD compared to moderate or severe cases. Therefore, the exercise capacity of patients with mild COPD should be estimated by the ISWT.