A comparison of six-minute walk distance between COPD patients with and without anemia

Abstract

       It is known that exercise capacity in patients with COPD is reduced. Also, anemia can reduce exercise capacity. However, there was no evidence of the reduction of exercise capacity in anemic COPD patients. The aim of this study was to compare the six-minute walk distance (6MWD), the heart rate, and the oxygen saturation immediately after the test (HRim and SpO2im) among the normal subjects and the COPD patients with and without anemia during six-minute walk test (6MWT). Fifty one sedentary elderly subjects were recruited into this study. Thirty four subjects were diagnosed as COPD. According to their hemoglobin level, they were divided into two groups: the anemic group and the non-anemic group (11.58 ± 0.72 g/dL vs. 13.21 ± 1.00 g/dL; p<0.05). Thirty five apparently healthy subjects were used as the control group. The spirometry maneuvers and the 6MWT were performed in all subjects. Additionally, blood samples were collected to identify their hemoglobin level. The lowest hemoglobin level was found in the anemic group compared with the non-anemic and the control group (11.58 ± 0.72 g/dL vs. 13.21 ± 1.00 g/dL vs. 13.08 ± 0.32 g/dL). The shortest 6MWD was statistically showed in the anemic group compared with the non-anemic and the control group (300.12 ± 88.55 m. vs. 390.12 ± 50.75 m. vs. 470.35 ± 43.10 m; p< 0.05). The SpO2im in the anemic group was statically significant difference among the groups (84.82 ± 6.69% vs. 90.06 ± 7.11% vs. 96.65 ± 2.62%; p< 0.05). However, the HRim was not different among the groups. Also, moderate to very severe COPD patients with anemia have reduced 6MWD.

Bull Chiang Mai Assoc Med Sci 2015; 48(1): 67-74. Doi: 10.14456/jams.2015.23