PURPOSE: 6 minute walk distance is increasingly being used for functional assessment of patients with COPD in clinical and research facility. In this study we have evaluated six minute walk test in relation of disease severity (GOLD classification) in COPD patients. Predictive value of six minute walk test for adverse outcome was also studied.
METHODS: 76 patients (mean age 64.3) of varying disease severity were enrolled in this study. All patients underwent spirometry and performed two six minute walk test, done one hour apart, as per ATS guideline. All patients were followed for period of one year for any adverse outcome. Adverse outcome was defined as exacerbation resulting hospital admission or death. Follow up rate was 78%.
RESULTS: All patients were classified in to four groups, as per GOLD classification. There were 6 patients (7.8%) with mild disease, 17 patients (22.3%) with moderate, 24 patients (31.5%) with severe and 29 (38.15%) with very severe disease. All patients with mild to moderate disease were able to walk 350 meter distance (460 mt +_45 mt).No significant difference was found in this group. Most patients (19 patients -79.16%) with severe disease were able to walk 350 meter(374+_64 meter).In patients with very severe disease only 9 patients (31.03%) were able to complete 350 meter distance(268+_110 meter).In period of follow up there were 34 adverse events including 6 death. All death events were seen in patients with very severe disease ,who were able to walk <180 meter. Among 28 hospital admission 19 (67.8%) were seen in patients with very severe disease ,8 (28.57%) admission in patients with severe disease and only one admission in patients with moderate disease.
CONCLUSION: There was no significant difference in six minute walk distance in patients with mild to moderate disease. As FEV1 fall below 50% of predicted there was reduction in walk distance.
CLINICAL IMPLICATIONS: Six minute walk distance is a useful prognostic tool in predicting the adverse outcome in patients with severe and very severe COPD.
DISCLOSURE: Sudhir Agarwal, No Financial Disclosure Information; No Product/Research Disclosure Information