Six-minute walk test in Chinese adults with clinically stable bronchiectasis: association with clinical indices and determinants

Abstract

Background:

The profiles of 6-minute walk distance (6MWD) in adults with clinically stable bronchiectasis in Chinese adult patients with bronchiectasis are unclear.

Objectives:

To delineate the 6MWD by stratification of clinical indices, and to investigate the factors associated with reduced 6MWD in Chinese adults with clinically stable bronchiectasis.

Methods:

We recruited 141 adult bronchiectasis patients (mean age: 44.3 ± 13.9 years). Demography, radiology, spirometry, diffusing capacity, etiology, sputum bacteriology, modified Medical Research Council dyspnea scale (MMRC) and quality of life were assessed. The safety profile of the measurement was also examined.

Results:

Lower levels of 6MWD were associated with older age (>50 years), higher HRCT total score, presence of cystic bronchiectasis, bilateral bronchiectasis, reduced diffusing capacity, higher MMRC score, and higher SGRQ scores. Correlation coefficients between 6MWD and spirometry and quality of life scores were different in patients with 6MWD higher and lower than lower limit of normal. D_LCO being less than 80% predicted (OR = 3.13, 95% CI: 1.32–7.43, P = 0.01) and MMRC scale between 1 and 4 (OR = 6.42, 95% CI: 2.27–18.18, P < 0.01) were the factors associated with 6MWD being less than the lower limit of normal (80% predicted value). No severe adverse events were reported.

Conclusion:

The 6MWD could be safely measured in adult patients with bronchiectasis and is poorly associated with clinical parameters. D_LCO less than 80% predicted and higher MMRC scale are independent predictors of 6MWD below the lower limit of normal. Our findings will provide a reference for management of bronchiectasis patients in mainland China.

Keywords: :

• Bacteriology
• Bronchiectasis
• Etiology
• Quality of life
• Radiology
• Six-minute walk test

Transparency

Declaration of funding

This study was supported by Changjiang Scholars and the Innovative Research Team in University No. ITR0961, The National Key Technology R&D Program of the 12th National Five-year Development Plan No. 2012BAI05B01 and National Key Scientific & Technology Support Program: Collaborative innovation of Clinical Research for chronic obstructive pulmonary disease and lung cancer No. 2013BAI09B09 (to N.-s.Z., R.-c.C. and J.-p.Z.), National Natural Science Foundation No. 81400010 and 2014 Scientific Research Projects for Medical Doctors and Researchers from Overseas, Guangzhou Medical University No. 2014C21 (to W.-j.G.). None of this funding had any influence on our study.

Author contributions: W.-j.G., Y.-h.G. and G.X. drafted the manuscript; Z.-y.L., Y.T., J.-p.Z., R.-c.C. and N.-s.Z. were responsible for patient recruitment; W.-j.G., Y.-h.G., G.X., H.-m.L. and Z.-m.L. collected individual data; W.-j.G., Y.-h.G. and G.X. performed statistical analyses; W.-j.G., Y.-h.G., G.X., R.-c.C. and N.-s.Z. contributed to study conception; R.-c.C. and N.-s.Z. provided critical review of the manuscript and approved the final submission.

Declaration of financial/other relationships

W.-j.G., Y.-h.G., G.X., Z.-y.L., Y.T., H.-m.L., Z.-m.L., J.-p.Z., R.-c.C., and N.-s.Z. have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article.

CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgment

We wholeheartedly thank Kenneth Wah-Tak Tsang and June Sun (Hong Kong University, Hong Kong SAR, China) for their valuable comments. We also wish to thank Wen-ming Liu (Biorad Inc., Guangzhou branch) for his technical support.