Clinical, biochemical, and radiological characterization of the calcinosis in a cohort of Mexican patients with systemic sclerosis

Calcinosis is a frequent complication of systemic sclerosis (SSc) that is usually located in extremities but may occur across the board. The aim of our study was to identify and quantify the distribution of calcinosis in a cohort of Mexican patients with SSc and its association with clinical features and autoantibodies. A cohort of patients with SSc (2013 ACR/EULAR criteria), classified in diffuse cutaneous (dcSSc) and limited cutaneous (lcSSc) (Le Roy criteria), was studied. For their analysis, patients were allocated into those with and without calcinosis (clinical and/or radiological). The evaluation included the modified Rodnan scale for skin and Medsger disease severity scale (DSS). Calcium, phosphorus, vitamin D, and parathyroid hormone (PTH) and antinuclear antibodies and extractable nuclear antigens were determined in serum. A total of 109 patients were included, 41 (37 %) with and 68 (63 %) without calcinosis. Calcinosis was more frequent in patients with dcSSc (55 vs 27 %). In total, we identified 354 sites with calcinosis and mean per patient of 12.0 ± 9.1; the most common sites affected were the hands (83 %), proximal upper extremity (27 %), and proximal lower extremity (22 %). Patients with calcinosis had a higher score of Rodnan scale, Mesdger DSS, and frequency of anti-nucleolar and anti-Scl-70 antibodies compared to those without calcinosis. Abnormal PTH elevation was found in 35 % of patients with calcinosis and 23 % without it. The prevalence of calcinosis is high in Mexican patients with SSc, especially in diffuse variety, and is associated with increased severity of disease.