Abstract

© 2015 Wolters Kluwer Health, Inc. PURPOSE: Prior research has shown a significant relationship between 6-minute walking distance and health-related quality of life in patients with chronic obstructive pulmonary disease. However, few studies have examined this relationship above and below the 350-m threshold that prognosticates survival and whether serum biomarkers could provide insight into the causes of quality-of-life differences above and below this threshold. METHODS: Measures of lung function, 6MWD, and HRQOL were compared in patients with COPD. Differences in HRQOL domains and serum biomarkers were compared in patients whose 6MWD were > or 350 m, surfactant protein D levels were associated with higher SF-36 scores in general pain, vitality, and social functioning. CONCLUSIONS: In COPD, there is an association between 6MWD and the physical domains of the SF-36 and SGRQ in those patients walking 350 m are not related to systemic inflammation. The association between interleukin 8 with nonphysical domains in patients with 6MWD < 350 m suggests that inflammation may play a larger role in the perceptive domain than previously recognized.