6MWT Reveals early physiological impairment in fibrotic interstitial lung diseases

Rationale Early prediction of lung function decline remains challenging in idiopathic pulmonary fibrosis (IPF) and fibrotic interstitial lung diseases (fibrotic ILD). We evaluated whether oxygen desaturation during the 6-minute walk test (6MWT) predicts forced vital capacity (FVC) decline and long-term outcomes. Methods We analyzed data from two independent cohorts: the nationwide Japanese Idiopathic Interstitial Pneumonias (JIPS) Registry and an external IPF cohort (K-Junko Study). Hazard ratios (HRs) were estimated for each 6MWT parameter to identify variables associated with FVC decline and to determine optimal thresholds. Sensitivity analyses were conducted using Fine–Gray models. The performance of the predictive model was assessed using calibration plots and the C-index. Results In JIPS IPF (n=457) and K-Junko IPF (n=318), an SpO₂ change of≤−6% during the 6MWT independently predicted ≥5% FVC decline in both cohorts (JIPS HR 1.292; K-Junko HR 1.480). Moreover, SpO₂ change during the 6MWT was significantly associated with FVC change in the subsequent year, and this association persisted over five consecutive years in JIPS IPF. The nomogram demonstrated moderate discrimination (C-index: 0.619 [training] and 0.632 [validation]) and fair calibration. A composite profile meeting all three criteria (FVC ≥80%, SpO₂ change>−6%, 6MWD ≥420 m) identified patients with favorable transplant-free survival. In JIPS non-IPF fibrotic ILD (n=387), SpO₂ change remained the sole independent predictor of ≥5% FVC decline (HR 1.350). Conclusion SpO₂ change during the 6MWT predicts FVC decline and outcomes across fibrotic ILD, and its incorporation into routine assessment may enable earlier risk stratification and facilitate timely intervention.

Authors

Institutions

Publication Details

Journal
ERJ Open Research
Published
2026-07-23
DOI
https://doi.org/10.1183/23120541.00691-2026
Primary Topic
Interstitial Lung Diseases and Idiopathic Pulmonary Fibrosis
Type
article
Field-Weighted Citation Impact
0.00

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

6MWT Reveals early physiological impairment in fibrotic interstitial lung diseases

Koji Sakamoto, Hirotaka Nishikiori, Tomoo Kishaba, Yoshiaki Zaizen et al.
ERJ Open Research
Interstitial Lung Diseases and Idiopathic Pulmonary Fibrosis
article

6MWT Reveals early physiological impairment in fibrotic interstitial lung diseases

Koji Sakamoto, Hirotaka Nishikiori, Tomoo Kishaba, Yoshiaki Zaizen, Yoshitaka Oyamada, Osamu Narumoto, Hidekazu Matsushima, Ryo Okuda, Susumu Sakamoto, Mitsuhiro Abe, Hidenori Ichiyasu, Hirofumi Chiba, Hiroshi Ishimoto, Yasuhiko Koga, Kazuhiro Yatera, Tomohiro Handa, H. Yamauchi, Ichiro Kuwahira, Hirotsugu Ohkubo, Tomoyuki Fujisawa, Kazuhiro Usui, JIPS registry collaborators, Hiroaki Nakagawa, Dai Hashimoto, Toshiaki Matsuda, Takashi Ogura, Takafumi Suda, Masahiro Kimura, Hiromi Tomioka, Kunihiko Kobayashi, Tetsuji Kawamura, Toshihiro Nukiwa, Yuriko Takeda, Osamu Nishiyama
article en

Abstract

Rationale Early prediction of lung function decline remains challenging in idiopathic pulmonary fibrosis (IPF) and fibrotic interstitial lung diseases (fibrotic ILD). We evaluated whether oxygen desaturation during the 6-minute walk test (6MWT) predicts forced vital capacity (FVC) decline and long-term outcomes. Methods We analyzed data from two independent cohorts: the nationwide Japanese Idiopathic Interstitial Pneumonias (JIPS) Registry and an external IPF cohort (K-Junko Study). Hazard ratios (HRs) were estimated for each 6MWT parameter to identify variables associated with FVC decline and to determine optimal thresholds. Sensitivity analyses were conducted using Fine–Gray models. The performance of the predictive model was assessed using calibration plots and the C-index. Results In JIPS IPF (n=457) and K-Junko IPF (n=318), an SpO₂ change of≤−6% during the 6MWT independently predicted ≥5% FVC decline in both cohorts (JIPS HR 1.292; K-Junko HR 1.480). Moreover, SpO₂ change during the 6MWT was significantly associated with FVC change in the subsequent year, and this association persisted over five consecutive years in JIPS IPF. The nomogram demonstrated moderate discrimination (C-index: 0.619 [training] and 0.632 [validation]) and fair calibration. A composite profile meeting all three criteria (FVC ≥80%, SpO₂ change>−6%, 6MWD ≥420 m) identified patients with favorable transplant-free survival. In JIPS non-IPF fibrotic ILD (n=387), SpO₂ change remained the sole independent predictor of ≥5% FVC decline (HR 1.350). Conclusion SpO₂ change during the 6MWT predicts FVC decline and outcomes across fibrotic ILD, and its incorporation into routine assessment may enable earlier risk stratification and facilitate timely intervention.

ERJ Open Research
Kurume University (JP), Kagoshima University (JP), Toho University (JP), Sendai University (JP), Hamamatsu University (JP), Sapporo Medical University (JP), Jichi Medical University (JP), Shohoku College (JP), Chiba University (JP), Shiga University of Medical Science (JP), Gunma University (JP), University of Occupational and Environmental Health Japan (JP), Kyoto University (JP), NTT Medical Center (JP), Hamamatsu University School of Medicine (JP), Nagoya City University (JP), Tokyo Medical Center (JP), Toho University Omori Medical Center (JP), Kindai University Sakai Hospital (JP), Matsudo City Hospital (JP), Okinawa Prefectural Chubu Hospital (JP), Kumamoto University Hospital (JP), Himeji Medical Center (JP), Seirei Hamamatsu General Hospital (JP), Saitama International Medical Center (JP), National Hospital Organization (JP), Kobe City Medical Center West Hospital (JP), Kanagawa Cardiovascular and Respiratory Center (JP), Saitama Red Cross Hospital (JP), Tokyo National Hospital (JP), JR Tokyo General Hospital (JP), Nagasaki University Hospital (JP), Nagoya University (JP), Saitama Medical University (JP), Yokohama City University (JP)
Boehringer Ingelheim Japan
Peace, Justice and strong institutions, Reduced inequalities
Openalex Percentile: Top 9%
Interstitial Lung Diseases and Idiopathic Pulmonary Fibrosis
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.