Figure 1.

Flow chart showing the distribution of the study patients and stratification of the digital ulcer (DU) outcome set. In total, 637 patients with systemic sclerosis were screened. After exclusion of screening failures, ineligible patients, premature discontinuations, and patients not assigned to case or noncase categories, the DU outcome evaluable set (n = 591) was obtained. Because the variables that influence the occurrence of a new DU were thought to be different in the DU history group (those with a history of DUs or with DUs at enrollment) versus the no DU history group (those without a history of DUs), the data analysis was stratified in the same two study arms.