Clinical impact of forced vital capacity on exercise performance in patients with chronic obstructive pulmonary disease

Seong Mi Moon; Jun Hyeok Lim; Yun Soo Hong; Kyeong-Cheol Shin; Chang Youl Lee; Do Jin Kim; Sang Haak Lee; Ki Suck Jung; Chang-Hoon Lee; Kwang Ha Yoo; Hyun Lee; Hye Yun Park

doi:10.21037/jtd-20-1098a

Clinical impact of forced vital capacity on exercise performance in patients with chronic obstructive pulmonary disease

J Thorac Dis. 2021 Feb;13(2):837-846. doi: 10.21037/jtd-20-1098a.

Authors

Seong Mi Moon¹, Jun Hyeok Lim², Yun Soo Hong³, Kyeong-Cheol Shin⁴, Chang Youl Lee⁵, Do Jin Kim⁶, Sang Haak Lee⁷, Ki Suck Jung⁸, Chang-Hoon Lee⁹, Kwang Ha Yoo¹⁰, Hyun Lee¹¹, Hye Yun Park¹²

Affiliations

¹ Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, South Korea.
² Division of Pulmonology, Department of Internal Medicine, Inha University Hospital, Inha University School of Medicine, Incheon, South Korea.
³ Department of Epidemiology and Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA.
⁴ Division of Pulmonology and Allergy, Regional Center for Respiratory Disease, Yeungnam University Medical Center, Daegu, South Korea.
⁵ Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Chuncheon Sacred Heart Hospital, Hallym University, Chuncheon, Gangwon-do, South Korea.
⁶ Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, South Korea.
⁷ Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Eunpyeong St. Mary's Hospital, College of Medicine, Department of Internal Medicine, The Catholic University of Korea, Seoul, South Korea.
⁸ Division of Pulmonary Medicine, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University Medical School, Anyang, South Korea.
⁹ Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea.
¹⁰ Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, South Korea.
¹¹ Department of Internal Medicine, Hanyang University College of Medicine, Seoul, South Korea.
¹² Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.

Abstract

Background: Forced vital capacity (FVC) has been suggested to be a good biomarker for decreased exercise performance in patients with chronic obstructive pulmonary disease (COPD). However, as FVC is highly correlated with forced expiratory volume in 1 second (FEV₁), the relationship between FVC and exercise capacity should be assessed within the category of FEV1, i.e., COPD severity. However, this was not considered in previous studies. Thus, limited data are available on the association between reduced FVC and exercise capacity measured by 6-min walk distance (6MWD) based on COPD severity.

Methods: We performed a cross-sectional study using data from the Korean COPD Subgroup Study (KOCOSS) cohort. We evaluated 1,386 patients with moderate (n=895) and severe-to-very severe (n=491) COPD. Reduced FVC was defined as FVC <80% predicted and short 6MWD as <350 m. Multivariable logistic regression was used to evaluate the association between reduced FVC and short 6MWD.

Results: There were no significant differences in respiratory symptoms and quality of life between the patients with reduced FVC and those with preserved FVC. However, patients with reduced FVC had shorter 6MWD (30.5 cm in moderate and 34.5 cm in severe-to-very severe COPD) and higher BODE index scores than those with preserved FVC. The cubic spline model revealed 6MWD peaked around 93% predicted of FVC in moderate COPD, whereas FVC showed a positive association with 6MWD in severe-to-very severe COPD. Multivariable analyses showed that reduced FVC was significantly associated with short 6MWD in both moderate [adjusted odds ratio (aOR) =1.44, 95% confidence interval (CI): 1.03-2.02] and severe-to-very severe (adjusted OR =1.55, 95% CI: 1.01-2.40) COPD.

Conclusions: Reduced FVC was significantly associated with shorter 6MWD in moderate-to-very severe COPD patients, suggesting that reduced FVC might be reflective of 6MWD-measured exercise capacity in moderate-to-very severe COPD.

Keywords: 6-min-walk test (6MWT); Chronic obstructive pulmonary disease (COPD); forced vital capacity (FVC).