Clinical course and factors associated with progressive acro-osteolysis in early systemic sclerosis: a retrospective cohort study

To examine clinical course of early systemic sclerosis (SSc) and identify factors for progression of acro-osteolysis by a retrospective cohort study. Dual time-point hand radiography was performed at median interval (range 3.0 ± 0.4 years) in 64 recruited patients. Progressive acro-osteolysis was defined as the worsening of severity of acro-osteolysis according to rating scale (normal, mild, moderate, and severe). Incidence of the progression was determined. Cox regression was analyzed for the predictors. A total of 193.6 per 100 person-years, 19/64 patients had progressive acro-osteolysis with incidence of 9.8 per 100-person-years (95% CI 6.3-15.4). The median time of progressive acro-osteolysis was 3.5 years. Rate of progression increased from 1st to 3rd years follow-up with the progression rate at 1-, 2- and 3-years were 0, 2.0 and 18.3%, respectively. Patients with positive anti-topoisomerase I tended to have more progressive acro-osteolysis but no significant predictors on Cox regression. 44%, 18%, and 33% of who had no, mild, and moderate acro-osteolysis previously developed progression and 10 turned to be severe acro-osteolysis. In conclusion, the incidence of progressive acro-osteolysis was uncommon in early SSc but the rate of progression was pronouncedly increasing after three years follow-up. A half of the patients progressed to severe acro-osteolysis.