Article

Prior research has shown a significant relationship between 6-minute
walking distance (6MWD) and health-related quality of life (HRQOL) in patients
with chronic obstructive pulmonary disease (COPD). 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. RESULTS: In patients walking < 350 m,
scores in the physical domains of the SF-36 and the St. George's Respiratory
Questionnaire (SGRQ) were significantly different from scores of their
counterparts with greater 6MWD. However, there was no association between any
biomarkers and the physical domains of the SF-36 and the SGRQ. In patients
walking < 350 m, only the IL-8 levels were associated with lower scores in SF-36
domains of emotional role, pain, vitality, and mental health (average r = -0.702;
P = .01). In contrast, in patients walking > 350 m, surfactant protein D levels
were associated with higher SF-36 scores in general pain, vitality, and social
functioning (average r = 0.42; P = .04). 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. The physical differences between patients walking < or
> 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.

Langue : ANGLAIS