A score of risk factors associated with ischemic digital ulcers in patients affected by systemic sclerosis treated with iloprost

A single series of patients affected by systemic sclerosis (SSc) and cyclically treated with iloprost was reviewed in order to evaluate the incidence of digital ulcers (DUs) and to compare the characteristics between the patients with and without this painful and disabling vascular complication. The record charts of 85 SSc patients were revised. Ischemic DUs and scleroderma contracture ulcers were separately considered. Twenty-nine subjects developed ischemic DUs during the course of the disease; whereas, scleroderma contracture ulcers occurred in six subjects. Ischemic DUs were associated with younger age at scleroderma onset, a longer disease duration, a longer time delay from scleroderma diagnosis to iloprost therapy, a bigger skin involvement, the presence of joint contractures, a videocapillaroscopic late pattern, a history of smoking, and of corticosteroids therapy. After the exclusion of four subjects with concomitant peripheral arterial disease, a forward-stepwise logistic regression analysis showed that only four variables, i.e., age at scleroderma onset, delay in beginning iloprost therapy, history of smoking, and presence of joint contractures remained significantly associated with ischemic DUs. In a score reflecting the sum of these four risk factors, the prevalence of ischemic DUs increased progressively from the lowest to the highest value of the score. The predictivity of this model was evaluated by the receiver-operating characteristics curve, with an estimated area under the curve of 0.836 with 95% confidence interval from 0.736 to 0.937. All the patients with scleroderma contracture ulcers were characterized by both diffuse pattern of disease and positivity for anti-Scl70 antibody. In this retrospective study, scleroderma patients with ischemic DUs are characterized by early disease onset, delay in beginning iloprost therapy, smoking habit, and presence of joint contraction. A score reflecting the sum of these factors may be useful to predict the risk of developing ischemic DUs.