Clinical features and risk factors analysis in adult dermatom yositis with calcinosis

Objective To identify clinical features and risk factors in adult dermatomyositis (DM) with calcinosis. Methods Four hundred and eighty patients' clinical data were collected. The correlation between calcinosis and no calcinosis in adult DM were calculated by t test, χ2 test and Mann-whitney U test. Multi-factor logistic regression model was established to analyze independent factors for adult DM with calcinosis. Results Calcinosis occurred in 22 cases among these 480 patients with DM. The incidence of adult DM with calcinosis was 4.6%. Calcinosis was most common in the extremities and trunks. Patients with calcinosis had a longer disease duration [48(24, 120) months vs 10(3, 24) months, U=1993, P=0.000)] and more myothenia (95.5% vs 76.9%, χ2=4.192, P=0.038), panniculitis (9.1% vs 0.4%, P=0.011), periungual erythematosus (22.7% vs 5.89%, χ2=7.044, P=0.008), skin ulcer(50.0% vs 5.2%, χ2=55.767, P=0.000), Raynaud's phenomenon (27.5% vs 8.1%, χ2=3.956, P=0.047). The anti-NXP2 antibody (27.3% vs 3.9%, χ2=19.416, P=0.000) and anti-MDA5 antibody (31.8% vs 12.9%, χ2=4.851, P=0.028) were more frequently found in patients with calcinosis. Multi-factor logistic regression showed that anti-NXP2 antibody [OR=10.899, 95%CI (2.593, 45.816), P=0.001], long diseases duration [OR=1.105, 95%CI(1.008, 1.021), P=0.000] and skin ulcer [OR=31.585, 95%CI(10.683), 93.387, P=0.000] were risk factors for adult DM with calcinosis. Conclusion The incidence of calcinosisis in adult DM is 4.5% in our cohort. Patients with calcinosis are adistinct clinical subset of adult DM. Long disease duration, skin ulcer and anti-NXP2 positive are independent risk factors for adult DM with calcinosis. Key words: Dermatomyositis; Risk factor; Cohort study; Calcinosis