A 6-minute walk (6MWT) test was found to be an effective means of assessing overall prognosis of patients with systemic sclerosis, as per a study published in the August edition of The Journal of Rheumatology. To test the efficacy of the 6MWT, researchers conducted a 6 year observational study using systemic sclerosis patients who underwent a minimum of two 6 minute walk tests within at least a 3 month interval and had routine clinical, biological, and functional evaluations. As per American Thoracic Society guidelines, researchers conducted each 6MWT twice to assess reproducibility of 6-minute walk distance, reporting the highest score for further analysis.
Analyzing the 56 patients included (38 female, age 46 ± 12.7 years), researchers found that the mean 6MWD was roughly 457, with an intraclass correlation coefficient of 0.996. Multivariate linear regression analysis found that sex, modified Rodnan skin score, tendon friction rub, Scleroderma Health Assessment Questionnaire, muscle disability score, and left ventricular ejection fraction were all independently associated with lower 6MWD. They also found the 6MWD at first referral to be an independent predictor of overall mortality and systemic sclerosis mortality. Of the 8 deaths reported, 87.5% were systemic sclerosis related.
The researchers note that patients who were in very advanced stages of disease were not able to perform the 6MWT due to joint pain, foot calcinosis, or muscle weakness. They also add that the 6MWT does not cover all the patients with systemic sclerosis, despite the strong reproducibility of 6MWD.
— J Rheum (@jrheum) August 2, 2018