Six-minute walk test in or out in evaluation of systemic sclerosis patients?

Abstract

Objective. Interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) are the leading causes of death in systemic sclerosis (SSc) patients. Although the six-minute walk test (6MWT) is used for evaluating ILD and PAH in clinical practice, no data are available on six-minute walk distance (6MWD) and oxygen desaturation in SSc patients without ILD and PAH. Methods. Prospectively collected data of the 6MWTs at baseline and 6-month follow-up of 300 consecutive SSc patients, included in the Ghent University Hospital Systemic Sclerosis Unit between May 2006 and April 2015 were analysed. Results. The mean 6MWD of 165 SSc patients without ILD and PAH who performed a 6MWT at baseline or at the 6-month visit was 484±93m. Patients in the diffuse cutaneous (DcSSc) subgroup (435±94m) walked less than in the limited (LSSc) subgroup (499±91m, p=0.04) and tended to walk less than in the limited cutaneous (LcSSc) subgroup (483±92m, p=0.15). In 115 SSc patients without ILD and PAH who walked at both moments, there was no significant difference between the 6MWDs (mean difference -7.60m 95%CI [-19.93m; 4.73m], p=0.23) and the oxygen desaturation was not statistically different in 102 of them (mean difference 0.41% 95%CI [-0.49%; 1.31%], p=0.37). Conclusion. In SSc without ILD and PAH, the 6MWD and oxygen desaturation is clinically stable over a 6 months period. The DcSSc subgroup walks less than the LSSc and the LcSSc subgroup.