Capillaroscopic skin ulcer risk index: A new prognostic tool for digital skin ulcer development in systemic sclerosis patients

Objective Digital ulcerations are one of the most frequent manifestations of microangiopathy in patients with systemic sclerosis (SSc; scleroderma). The early detection of SSc patients who are at high risk to develop digital ulcers could allow a preventive treatment of these complications with reduction of morbidity and social costs. The aim of our study was to develop a capillaroscopic skin ulcer risk index (CSURI) that can predict the onset of new digital ulcers by using nailfold videocapillaroscopy (NVC) in patients with SSc. Methods We performed NVC in 120 consecutive unselected patients with SSc (13 men, 107 women, mean ± SD age 56.1 ± 13.4 years, mean ± SD SSc duration 44.7 ± 60.7 months) to assess the total number of capillaries in the distal row (N), maximum loop diameter (D), number of megacapillaries (M), and the M:N ratio. Results Within 3 months since NVC examination, 35 of 120 patients experienced digital ulcers. A significant association between ischemic lesions and the M:N ratio, N, and D was observed; the combination of these parameters allowed us to develop the CSURI, which is characterized by the formula D × M:N2. A receiver operating characteristic curve analysis showed an area under the curve of 0.926 for ulcer appearance, with specificity and sensitivity of 85.9% and 94.3%, respectively, at the cutoff value of 2.94. Interestingly, 33 of 35 patients with new skin ulcers had a CSURI >2.94, but only 2 of 35 had a CSURI ≤2.94. Conclusion The proposed CSURI may represent a novel tool with the ability to predict the development of digital ulcers in patients with scleroderma.