SSc patients with OAB were characterized by old age, a long history of morbidity (15.4 vs. 11.2 years, p < .01), high anti-centromere antibody positive rate (75.9 vs. 44%, p < .05), high incidence of gastroesophageal reflux disease (93.1 vs. 73.3%, p < .05), low anti-SS-A antibody positive rate (6.9 vs. 26.8%, p < .05), and low incidence of internal lung disease (17.9 vs. 45.7%, p < .05) compared to SSc patients without OAB.