Presentation: Sub-Maximal Exercise Testing in the Prospective Assessment of Interstitial Lung Disease (ILD) Secondary to Systemic Sclerosis (SSc): Correlations with Objective and Subjective Measures of Parenchymal Lung Disease (2007)

14 Sub-Maximal Exercise Testing in the Prospective Assessment of Interstitial Lung Disease (ILD) Secondary to Systemic Sclerosis (SSc): Correlations with Objective and Subjective Measures of Parenchymal Lung Disease

Introduction: The 6-minute walk test (6MWT) is an accessible measure of outcome in parenchymal lung disease in SSc. We evaluated correlations of 6MWT with other established parameters in a well characterized group of patients with ILD secondary to SSc followed prospectively for 12 months.
Methods: 65 patients with SSc-ILD receiving placebo in a multi-center, randomized trial were evaluated at baseline and at 12 months with 6MWT, Borg dyspnea index, FVC, and DLco. Mean age was 54.5 ± 11 and mean disease duration 5.2 ± 6.6 years. 48 subjects (73.8%) were female. 29 (45%) were classified as limited and 36 (55%) as diffuse SSc.
Results: Mean 6MWT at baseline was 408 ± 87m and at 12 months 406.5 ± 84.2m; mean Borg dyspnea scale was 2.7 ± 2 at baseline and 2.5 ± 2 at 12 months; mean FVC at baseline was 2.6 ± 0.8L and at 12 months 2.6 ± 0.9L; mean DLco at baseline was 10.1 ± 4.7mmol/kPa.min and at 12 months 10.2 ± 4.6 mmol/kPa.min. Correlations between the 6MWT and Borg dyspnea index, FVC and DLco in the limited and diffuse SSc groups were:
Limited SSc at 12 Baseline - - - Limited SSc at 12 months
6MWTBorg IndexFVCDLco6MWTBorg IndexFVCDLco
6MWT-baseline1-.441*.361.511**.652**.044.319.511**
Borg-baseline-.441*1-.273-.240-.240.605**-.170-.194
FVC-baseline.361-.2731.425*.296-.362.957**.383*
DLco-baseline.511**-.240.425*1.411**-.252.428*.929**
6MWT-12 months.652**-.240.296.411*1-.328.346.451*
Borg-12 months-.044.605*-.362-.252-.3281-.340-.227
FVC-12 months.319-.170.957**.428*.346-.3401.414*
DLco-12 months.511**-.194.383*.929**.451*-.227.414*1
Diffuse SSc at 12 Baseline  - - - Diffuse SSc at 12 months
6MWTBorg IndexFVCDLco6MWTBorg IndexFVCDLco
6MWT-baseline1-.307.200.063.680**-.395*.108.134
Borg-baseline-.3071.073-.218-.260.597**.121-.269
FVC-baseline.200.0731-066.403*-.043.980**-.084
DLco-baseline.063-.218-.0661.147-.223-.063.958**
6MWT-12 months.680**-.250.403*.1471-.375*.368*.207
Borg-12 months-.395*.597**-.043-.223-.375*1.040-.310
FVC-12 months.108.121.980**-.063.368*.0401-.077
DLco-12 months.134-.269-.084.958**.207-.310-.0771

* P≤ .01 (2-tailed), ** P≤.05 level (2-tailed)
Conclusions: These data confirm the stability of SSc-ILD over 12 months of observation and the high reproducibility of the 6MWT, Borg index, FVC and DLco. Data in the limited SSc sub-group show significant correlations between the 6MWT and DLco at baseline and follow-up as well as with the Borg dyspnea index at baseline. The diffuse SSc sub-group shows significant correlations between 6MWT and Borg index and FVC at follow-up but no correlation with DLco. Future interventional studies might address these potentially important differences between SSc subgroups.

  E. Schiopu, Actelion, 2; Actelion, 8; A.J. Impens, Actelion, 2; K. Phillips, None; C.P. Denton, Actelion, 2; Actelion, 5; D.E. Furst, Actelion, 2; Actelion, 5; L. Guillevin, Actelion, 5; Actelion, 2; L.J. Rubin, Actelion, 2; Actelion, 5; A.U. Wells, Actelion, 2; Actelion, 5; M. Matucci-Cerinic, Actelion, 2; Actelion, 5; G. Riemekasten, Actelion, 2; Actelion, 5; P. Emery, Actelion, 2; Actelion, 5; H. Chadha-Boreham, Actelion, 3; P. Charef, Actelion, 3; S. Roux, Actelion, 3; C.M. Black, Actelion, 2; Actelion, 5; J.R. Seibold, Actelion, 2; Actelion, 5.