Dyspnea and desaturation during exercise are essential assessment items for pulmonary rehabilitation. Characterizing patients using these 2 factors may be important for providing more effective pulmonary rehabilitation. This study aimed to categorize subjects with interstitial lung disease (ILD) using dyspnea and desaturation at the end of the 6-min walk test (6MWT).
Methods:
This was a retrospective study including 230 stable subjects with ILD who underwent 6MWT in our out-patient department at a general hospital in Japan. The modified Borg scale and oxygen saturation determined by SpO2 at the end of the 6MWT were used for cluster analysis using the k-means method with k = 4.
Results:
Subjects were classified into 4 characteristic clusters. SpO2 at the end of the 6MWT was lower in cluster 4 (80.5 ± 3.0%) than in clusters 1 (94.3 ± 2.0%), 2 (94.3 ± 1.9%), and 3 (87.9 ± 1.8%) and was lower in cluster 3 than in clusters 1 and 2. The modified Borg scale score at the end of the 6MWT was higher in clusters 2 (4 [3–8]), 3 (3 [0–9]), and 4 (4 [0–7]) than in cluster 1 (0.5 [0–2.0]) and was higher in cluster 2 than in cluster 3.
Conclusions:
Subjects with ILD were classified into 4 characteristic clusters using dyspnea and SpO2 at the end of the 6MWT. The 4 clusters are characterized as follows: Cluster 1 had mild desaturation and mild dyspnea; cluster 2 had mild desaturation and severe dyspnea; cluster 3 had both moderate desaturation and dyspnea, and cluster 4 had both severe desaturation and dyspnea. These classification data offer insight for individualized pulmonary rehabilitation for patients with ILD.
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References
1.
BjorakerJA, RyuJH, EdwinMK, et al. Prognostic significance of histopathologic subsets in idiopathic pulmonary fibrosis. Am J Respir Crit Care Med. 1998; 157(1):199–203.
2.
KozuR, JenkinsS, SenjyuH. Evaluation of activity limitation in patients with idiopathic pulmonary fibrosis grouped according to Medical Research Council dyspnea grade. Arch Phys Med Rehabil. 2014; 95(5):950–955.
3.
NakayamaM, BandoM, ArakiK, et al. Physical activity in patients with idiopathic pulmonary fibrosis. Respirology. 2015; 20(4):640–646.
4.
BahmerT, KirstenAM, WaschkiB, et al. Clinical correlates of reduced physical activity in idiopathic pulmonary fibrosis. Respiration. 2016; 91(6):497–502.
5.
HollandAE, FioreJFJr, BellEC, et al. Dyspnea and comorbidity contribute to anxiety and depression in interstitial lung disease. Respirology. 2014; 19(8):1215–1221.
6.
GlaspoleIN, ChapmanSA, CooperWA, et al. Health-related quality of life in idiopathic pulmonary fibrosis: data from the Australian IPF Registry. Respirology. 2017; 22(5):950–956.
7.
KhadawardiH, MuraM. A simple dyspnea scale as part of the assessment to predict outcome across chronic interstitial lung disease. Respirology. 2017; 22(3):501–507.
8.
NishiyamaO, TaniguchiH, KondohY, et al. Dyspnea at 6-min walk test in idiopathic pulmonary fibrosis: comparison with COPD. Respir Med. 2007; 101(4):833–838.
9.
ManaliED, LyberopoulosP, TriantafillidouC, et al. MRC chronic dyspnea scale: relationships with cardiopulmonary exercise testing and 6-min walk test in idiopathic pulmonary fibrosis patients: a prospective study. BMC Pulm Med. 2010; 10:32.
10.
LiJ, LiX, DengM, et al. Features and predictive value of 6-min walk test outcomes in interstitial lung disease: an observation study using wearable monitors. BMJ Open. 2022; 12(6):e055077.
11.
SchaefferMR, RyersonCJ, RamsookAH, et al. Neurophysiological mechanisms of exertional dyspnea in fibrotic interstitial lung disease. Eur Respir J. 2018; 51(1):1701726.
12.
CollardHR, PantilatSZ. Dyspnea in interstitial lung disease. Curr Opin Support Palliat Care. 2008; 2(2):100–104.
BreulsS, de AraujoCP, BlondeelA, et al. Physical activity pattern of patients with interstitial lung disease compared to patients with COPD: a propensity-matched study. PLoS One. 2022; 17(11):e0277973.
15.
RaghuG, CollardH, EganJJ, et al; ATS/ERS/JRS/ALAT Committee on Idiopathic Pulmonary Fibrosis. An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management. Am J Respir Crit Care Med. 2011; 183(6):788–824.
16.
TroyLK, YoungIH, LauEMT, CorteTJ. Exercise pathophysiology and the role of oxygen therapy in idiopathic interstitial pneumonia. Respirology. 2016; 21(6):1005–1014.
17.
NikoletouD, SterIC, LechCY, et al. Comparison of high-intensity interval training versus moderate-intensity continuous training in pulmonary rehabilitation for interstitial lung disease: a randomized controlled pilot feasibility trial. BMJ Open. 2023; 13(8):e066609.
18.
EatonT, YoungP, MilneD, WellsAU. Six-minute walk, maximal exercise tests: reproducibility in fibrotic interstitial pneumonia. Am J Respir Crit Care Med. 2005; 171(10):1150–1157.
19.
BuchMH, DentonCP, FurstDE, et al. Submaximal exercise testing in the assessment of interstitial lung disease secondary to systemic sclerosis: reproducibility and correlation of the 6-min walk test. Ann Rheum Dis. 2007; 66(2):169–173.
20.
TravisWD, CostabelU, HansellDM, et al; ATS/ERS Committee on Idiopathic Interstitial Pneumonias. An official American Thoracic Society/European Respiratory Society statement: update of the international multidisciplinary classification of the idiopathic interstitial pneumonias. Am J Respir Crit Care Med. 2013; 188(6):733–748.
21.
American Thoracic Society. ATS statement: guidelines for the 6-min walk test. Am J Respir Crit Care Med. 2002; 166:111–117.
22.
BansalV, HillK, DolmageTE, BrooksD, WoonLJ, GoldsteinRS. Modifying track layout from straight to circular has a modest effect on the 6-min walk distance. Chest. 2008; 133(5):1155–1160.
23.
KurimotoT, UsamiI, OhtsukaY, et al. Clinical issues in measuring oxygen desaturation during 6-min walk test using pulse oximeter. J Jp Soc Resp Care Rehab. 2016; 26(1):44–49 (in Japanese).
24.
BorgGA. Psychophysical bases of perceived exertion. Med Sci Sports Exerc. 1982; 14(5):377–381.
25.
ProvencherS, ChemlaD, HervéP, SitbonO, HumbertM, SimonneauG. Heart rate responses during the 6-min walk test in pulmonary arterial hypertension. Eur Respir J. 2006; 27(1):114–120.
26.
American Thoracic Society. Standardization of spirometry 1994 update. Am J Respir Crit Care Med. 1994; 152:1107–1136.
27.
Special Committee of Pulmonary Physiology, The Japanese Respiratory Society. Standard values of spirogram and arterial blood gas in normal Japanese subjects. J Jpn Respir Soc. 2001; 39:s1–s17 (in Japanese).
28.
NishidaO, KambeM, SewakwN, TakanoM, KawaneH. Pulmonary function in healthy subjects and its prediction, 5. Pulmonary diffusion capacity in adults. Rinsho Byouri. 1976; 24:941–947 (in Japanese).
29.
KandaY. Investigation of the freely available easy-to-use software “EZR” for medical statistics. Bone Marrow Transplant. 2013; 48(3):452–458.
30.
AdegunsoyeA, OldhamJM, ChungJH, et al. Phenotypic clusters predict outcomes in a longitudinal interstitial lung disease cohort. Chest. 2018; 153(2):349–360.
31.
WongAW, LeeTY, JohannsonKA, et al. A cluster-based analysis evaluating the impact of comorbidities in fibrotic interstitial lung disease. Respir Res. 2020; 21(1):322.
32.
TzanakisN, SamiouM, LambiriI, AntoniouK, SiafakasN, BourosD. Evaluation of health-related quality of life and dyspnea scale in patients with idiopathic pulmonary fibrosis. Correlation with pulmonary function tests. Eur J Intern Med. 2005; 16(2):105–112.
33.
LatsiPI, Du BoisRM, NicholsonAG, et al. Fibrotic idiopathic interstitial pneumonia: the prognostic value of longitudinal functional trends. Am J Respir Crit Care Med. 2003; 168(5):531–537.
34.
CollardHR, KingTEJr, BartelsonBB, VourlekisJS, SchwarzMI, BrownKK. Changes in clinical and physiologic variables predict survival in idiopathic pulmonary fibrosis. Am J Respir Crit Care Med. 2003; 168(5):538–542.
35.
RyersonCJ, BerkeleyJ, Carrieri-KohlmanV, PantilatSZ, LandefeldCS, CollardHR. Depression and functional status are strongly associated with dyspnea in interstitial lung disease. Chest. 2011; 139(3):609–616.
36.
RantalaHA, Leivo-KorpelaS, LehtoJT, LehtimäkiJT. Dyspnea on exercise is associated with overall symptom burden in patients with chronic respiratory insufficiency. Palliat Med Rep. 2021; 2(1):48–53.
37.
AgustiAG, RocaJ, GeaJ, WagnerPD, XaubetA, Rodriguez-RoisinR. Mechanisms of gas-exchange impairment in idiopathic pulmonary fibrosis. Am Rev Respir Dis. 1991; 143(2):219–225.
38.
Du PlessisJP, FernandesS, JamalR, et al. Exertional hypoxemia is more severe in fibrotic interstitial lung disease than in COPD. Respirology. 2018; 23(4):392–398.
39.
AlfieriV, CrisafulliE, ViscaD, et al. Physiological predictors of exertional oxygen desaturation in patients with fibrotic interstitial lung disease. Eur Respir J. 2020; 55(2):1901681.
40.
LamaVN, FlahertyKR, ToewsGB, et al. Prognostic value of desaturation during a 6-min walk test in idiopathic interstitial pneumonia. Am J Respir Crit Care Med. 2003; 168(9):1084–1090.
41.
HollandAE, HillCJ, GlaspoleI, GohN, DowmanL, McDonaldCF. Impaired chronotropic response to 6-min walk test and reduced survival in interstitial lung disease. Respir Med. 2013; 107(7):1066–1072.
42.
OishiK, MatsunagaK, Asami-NoyamaM, et al. The 1-min sit-to-stand test to detect desaturation during 6-min walk test in interstitial lung disease. NPJ Prim Care Respir Med. 2022; 32(1):5.
43.
ChéhèreB, BougaultV, ChenivesseC, GrosboisJ-M, WallaertB. Cardiorespiratory adaptation during 6-min walk test in fibrotic idiopathic interstitial pneumonia patients who did or did not respond to pulmonary rehabilitation. Eur J Phys Rehabil Med. 2019; 55(1):103–112.
44.
HanadaM, KasawaraKT, MathurS, et al. Aerobic and breathing exercises improve dyspnea, exercise capacity, and quality of life in idiopathic pulmonary fibrosis patients: systematic review and meta-analysis. J Thorac Dis. 2020; 12(3):1041–1055.
45.
SharpC, AdamaliH, MillarAB. Ambulatory and short-burst oxygen for interstitial lung disease. Cochrane Database Syst Rev. 2016; 7(7):CD011716.
46.
HollandAE, HillCJ, GlaspoleI, GohN, McDonaldCF. Predictors of benefit following pulmonary rehabilitation for interstitial lung disease. Respir Med. 2012; 106(3):429–435.
47.
MatsuoS, OkamotoM, IkeuchiT, et al. Early intervention of pulmonary rehabilitation for fibrotic interstitial lung disease is a favorable factor for short-term improvement in health-related quality of life. J Clin Med. 2021; 10(14):3153.
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