PT  - JOURNAL ARTICLE
AU  - C. Casanova
AU  - C. G. Cote
AU  - J. M. Marin
AU  - J. P. de Torres
AU  - A. Aguirre-Jaime
AU  - R. Mendez
AU  - L. Dordelly
AU  - B. R. Celli
TI  - The 6-min walking distance: long-term follow up in patients with COPD
AID  - 10.1183/09031936.00071506
DP  - 2007 Mar 01
TA  - European Respiratory Journal
PG  - 535--540
VI  - 29
IP  - 3
4099  - http://erj.ersjournals.com/content/29/3/535.short
4100  - http://erj.ersjournals.com/content/29/3/535.full
SO  - Eur Respir J2007 Mar 01; 29
AB  - The 6-min walking distance (6MWD) test is used in clinical practice and research into patients with chronic obstructive pulmonary disease (COPD). However, little is known about natural long-term change in this parameter. The 6MWD was measured at baseline and then annually for 5 yrs in 294 patients with COPD and its annual rate of decline was determined. Forced expiratory volume in one second (FEV1) was also measured and the relationship between changes in both markers was explored. At baseline, the median 6MWD was 380 m (range 160–600 m). It declined by 19% (16 m·yr-1) over the 5 yrs compared with baseline in patients with American Thoracic Society/European Respiratory Society stage III COPD (FEV1 30–50% predicted) and by 26% (15 m·yr-1) in patients with stage IV COPD (FEV1 <30% pred). Over the 5-yr follow-up, the proportion of patients with a minimal clinically significant decline of 54 m increased with the severity of the disease. It was 24% in stage II, 45% in stage III, and 63% in stage IV disease. In contrast, the rate of decline of FEV1 was greater in patients with milder airflow obstruction and lesser in patients with lower absolute FEV1 values. In conclusion, the 6-min walking distance test provides increasingly useful information as the severity of chronic obstructive pulmonary disease increases.