Objectives Cardiopulmonary involvement (CPI) is a major cause of morbidity and mortality in systemic sclerosis (SSc). The 6 min walk test (6MWT) is widely used to assess functional capacity, but its ...

Model 1 (base model): follows the conceptual model highlighted above in Equation 1 ... meaning it could be expressed as a perfect linear combination of at least one of the included explanatory ...