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Pugnet, et al: Walk test in SSc
Personal non-commercial use only. The Journal of Rheumatology Copyright © 2018. All rights reserved.
Reproducibility and Utility of the 6-minute Walk Test in
Systemic Sclerosis
Grégory Pugnet, Zora Marjanovic, Christophe Deligny, Karine Boussardon, Ilham Benzidia,
Mathieu Puyade, Pauline Lansiaux, Els Vandecasteele, Vanessa Smith, and Dominique Farge
ABSTRACT. Objective. To assess the reproducibility and the utility of the 6-minute walk test (6MWT) in systemic
sclerosis (SSc).
Methods. All patients with SSc who underwent at least two 6MWT within a minimum 3-month interval
plus simultaneous routine clinical, biological, and functional evaluations were consecutively enrolled
in this observational study over 6 years. Following American Thoracic Society guidelines, each 6MWT
was repeated twice to assess the 6-minute walk distance (6MWD) reproducibility, with the highest
value being reported for subsequent analysis.
Results. Among 56 (38 female) included patients aged 46 ± SD 12.7 years, with 17 ± 10 modified
Rodnan skin score (mRSS) and 1 ± 0.8 Scleroderma Health Assessment Questionnaire (SHAQ) at
first referral, 277 6MWT evaluations (5 ± 3.9 6MWT per patient) were performed over 23 ± 22.5
months followup. Meanwhile, 8 deaths (87.5% SSc-related) occurred. The mean 6MWD absolute
value was 457 ± 117 m with a 4 ± 2.2 mean Borg dyspnea score. The 6MWD intraclass correlation
coefficient was 0.996 (95% CI 0.995–0.999, p < 0.0001). In multivariate linear regression analysis,
these factors were independently associated with a lower 6MWD: sex (R
2
= 0.47, p < 0.0001), mRSS
(R
2
= 0.47, p = 0.008), tendon friction rub (R
2
= 0.47, p = 0.003), SHAQ (R
2
= 0.47, p = 0.02), muscle
disability score (R
2
= 0.47, p = 0.03), DLCO% (R
2
= 0.47, p = 0.0008), and left ventricular ejection
fraction (R
2
= 0.47, p = 0.006). The 6MWD at first referral was an independent predictor for the overall
mortality (HR 0.99, 95% CI 0.988–0.999) and the SSc-related mortality (HR 0.99, 95% CI
0.988–0.999).
Conclusion. We show strong reproducibility for the 6MWD and confirm the 6MWT utility to assess
the overall prognosis of patients with SSc. (J Rheumatol First Release July 1 2018; doi:10.3899/
jrheum.170994)
Key Indexing Terms:
SYSTEMIC SCLEROSIS SCLERODERMA WALK TEST
SURVIVAL ANALYSIS REPRODUCIBILITY OF RESULTS
From the Service de Médecine Interne, CHU Toulouse Purpan; Faculté de
Médecine de Toulouse, Toulouse; Hématologie clinique et thérapie
cellulaire, and Unité de Médecine Interne, Maladies Auto-immunes et
Pathologie Vasculaire, UF 04, Centre de référence des maladies
auto-immunes systémiques rares d’Ile-de-France, Filière (FAI2R), AP-HP,
hôpital Saint-Antoine; Université Paris Diderot, Sorbonne Paris Cité,
Paris, France; Service de médecine interne, Centre national de référence
“Lupus, syndrome des antiphospholipides et autres maladies
auto-immunes systémiques rares,” Hôpital Pierre Zobda Quitman, CHU
de Martinique, Fort de France, Martinique; Service de Médecine Interne
et Maladies Infectieuses, CHU de Poitiers, Poitiers, France; Department
of Cardiology, Department of Internal Medicine, and Department of
Rheumatology, Ghent University Hospital, Ghent, Belgium.
G. Pugnet, MD, PhD, Service de Médecine Interne, CHU Toulouse
Purpan, and Faculté de Médecine de Toulouse; Z. Marjanovic, MD,
Hématologie clinique et thérapie cellulaire, AP-HP, hôpital Saint-Antoine;
C. Deligny, MD, PhD, Service de médecine interne, Centre national de
référence “Lupus, syndrome des antiphospholipides et autres maladies
auto-immunes systémiques rares,” Hôpital Pierre Zobda Quitman, CHU
de Martinique; K. Boussardon, MSc, Physiotherapist, Unité de Médecine
Interne, Maladies Auto-immunes et Pathologie Vasculaire, UF 04, Centre
de référence des maladies auto-immunes systémiques rares d’Ile-de-
France, Filière (FAI2R), AP-HP, Hôpital Saint-Louis; I. Benzidia, MD,
Unité de Médecine Interne, Maladies Auto-immunes et Pathologie
Vasculaire, UF 04, Centre de référence des maladies auto-immunes
systémiques rares d’Ile-de-France, Filière (FAI2R), AP-HP, Hôpital Saint-
Louis; M. Puyade, MD, Service de Médecine Interne et Maladies
Infectieuses, CHU de Poitiers; P. Lansiaux, PhD, Unité de Médecine
Interne, Maladies Auto-immunes et Pathologie Vasculaire, UF 04, Centre
de référence des maladies auto-immunes systémiques rares d’Ile-de-
France, Filière (FAI2R), AP-HP, Hôpital Saint-Louis; E. Vandecasteele,
MD, Department of Cardiology, Ghent University Hospital; V. Smith, MD,
PhD, Department of Internal Medicine, Ghent University, and Department
of Rheumatology, Ghent University Hospital; D. Farge, MD, PhD, Unité
de Médecine Interne, Maladies Auto-immunes et Pathologie Vasculaire,
UF 04, Centre de référence des maladies auto-immunes systémiques rares
d’Ile-de-France, Filière (FAI2R), AP-HP, Hôpital Saint-Louis, Université
Paris Diderot, Sorbonne Paris Cité.
Address correspondence to Prof. D. Farge, Unité de Médecine Interne,
Maladies Auto-immunes et Pathologie Vasculaire, UF 04, Centre de
référence des maladies auto-immunes systémiques rares d’Ile-de-France,
Filière (FAI2R), Hôpital Saint-Louis, 1 avenue Claude-Vellefaux, Paris
75010, France. E-mail: dominique.farge-bancel@aphp.fr; or Dr G.
Pugnet, Service de Médecine Interne, CHU Toulouse Purpan,
Faculté de Médecine de Toulouse, Toulouse 31059, France.
E-mail: pugnet.g@chu-toulouse.fr
Accepted for publication April 6, 2018.
The 6-minute walk test (6MWT) is a simple, submaximal
aerobic exercise test, currently used in idiopathic pulmonary
fibrosis, all types of pulmonary arterial hypertension (PAH),
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