Yuan S, Lian F, Chen D, Li H, Qiu Q, Zhan Z, Ye Y, Xu H, Liang L, Yang X. Clinical features and associated factors of abdominal pain in systemic lupus erythematosus. J Rheumatol 2013;40:2015–22. Drs. F. Lian and X. Yang contributed equally to this study and should be considered as co-first authors. Address correspondence also to Dr. Yang; E-mail: yang_xiu_yan{at}hotmail.com. We regret the omission.