Background Joint contractures as well as symptoms of cardiopulmonary involvement restrict the physical capacity of patients with systemic sclerosis (SSc). The six minute walk test (6MWT) is widely used in the assessment of physical capacity and to evaluate treatment efficacy. However, it is unclear how much the joint function of the patients influences the diagnostic value of the walking tests.
Objectives We performed a prospective, cross sectional, single center study to assess the 6MWT, the 10-meter walk test (10meterWT) in the context of the joint contractures. The relationship between the extent of joint-contractures to the major internal organ involvements including different forms of cardiopulmonary involvement was also examined.
Methods Ninety-six consecutive patients, 84 females and 12 males, 32 with diffuse cutaneous SSc (dcSSc), 64 with limited cutaneous SSc (lcSSc) were enrolled during their routine yearly scheduled check-up. Patients’ mean age was 56.2±12.7 years (±SD) with a mean disease duration of 8.8±7.5 years. The protocol included physical examination, echocardiography and 6MWT. Additionally, Health Assessment Questionnaire Disability Index (HAQ DI), and European SSc activity index were determine and the 10meterWT was also performed. Limitation in range of motion of the joints greater than 25% was considered “contracture”, and the number of contractures of each extremity was recorded.
Results The mean distance of the 6MWT was 363±66 m. Neither the number of contractures of the lower extremities, nor the number of the whole body’s all contractures showed significant correlation with the 6-minute walk distance in SSc. HAQ DI (p<0.001) and age (p<0.05) were independent predictors of the results of both walking tests. Predictors of 6MWT included the right ventricular systolic pressure, and the number of digital ulcers, while a trend for the presence of left heart failure was also found (p=0.057). Further significant determinants of the 10-meterWT were the extent of the joint restrictions of the lower extremities (p<0.01), and the disease activity index (p<0.05).
Conclusions The number of joint contractures does not influence significantly the applicability of 6MWT in SSc. The relation to the right ventricular systolic pressure underlines its applicability in characterizing patients with left or right heart dysfunction. The 10MWT where the patients are expected to walk only 10 meters as opposed to the hundreds of meters covered in the 6MWT, is the more sensitive indicator of the joint involvement.
Disclosure of Interest None Declared