CHICAGO – A simple new classification scheme that combines autoantibody specificity and extent of skin involvement could improve risk stratification of patients with systemic sclerosis, according to researchers at University College London.
“The Le Roy et al. classification of SSc [systemic sclerosis] into limited and diffuse cutaneous subtype remains the most commonly used classification system for systemic sclerosis, but autoantibodies are much better predictors of organ involvement, and while more sophisticated approaches exist, this proposed simple classification using antibodies and skin subset is relevant to clinical practice and could help risk stratification,” Svetlana I. Nihtyanova, MD, said at the annual meeting of the American College of Rheumatology.
Dr. Nihtyanova, a clinical research fellow at University College London,how she and her colleagues at UCL divided 1,025 SSc patients into 12 subgroups based on skin subset and autoantibodies and then conducted Kaplan-Meier estimates of survival and cumulative incidence of organ complications to rank these 12 subgroups by endpoint estimates. They merged subgroups with similar ranking in multiple endpoints, ending up with seven groups in the final classification.
Group 1 comprised anti–centromere antibody–positive limited cutaneous SSc (lcSSc) patients and accounted for 29% of patients.
“This was the subgroup with the highest survival (72%) and the lowest incidence of pulmonary fibrosis (13%) and scleroderma renal crisis (no cases) at 20 years from onset,” she said, noting that the incidence of pulmonary hypertension in this group was similar to the average for the whole cohort.
Group 2 comprised all anti–RNA polymerase antibody–positive subjects and accounted for 11% of patients. This group had the highest incidence of scleroderma renal crisis (SRC; 32% at 20 years), but other organ complications and survival were similar to the cohort average.
Group 3 comprised Scl-70–positive lcSSc patients, and accounted for 11% of patients.
“Although incidence of pulmonary fibrosis in this group was the second highest (69% at 20 years), other complications were rare,” Dr. Nihtyanova said, adding that this group had the lowest incidence of pulmonary hypertension (6%) and the second lowest incidence of SRC (3%) at 20 years.
Group 4, conversely, included Scl-70–positive dcSSc patients and accounted for 11% of patients, who had a very poor prognosis; they had the highest incidence of pulmonary fibrosis (91%) and cardiac scleroderma (14%), and the worst survival (41%) at 20 years, she said.
Group 5 included all U3 RNP–positive patients, accounting for 5% of patients.
“Although survival in this group was not bad (70% at 20 years), the group had the highest pulmonary hypertension incidence (40%) and the second highest incidence of cardiac SSc (11%) at 20 years,” she noted.
Groups 6 and 7 (comprising 22% and 11% of study subjects, respectively) included lcSSc and diffuse cutaneous SSc (dcSSc) patients with other antibody specificities. Group 6 had low overall SRC and cardiac SSc risk, while other outcomes were similar to the cohort average. Group 7, however, had poor prognosis, with the second lowest survival (42% at 20 years) and above average rates of organ disease, particularly pulmonary fibrosis and SRC, she said.
Overall, estimated survival for the entire cohort was 60% at 20 years from onset, and in that time frame 44% developed significant pulmonary fibrosis, 25% pulmonary hypertension, 7% SRC, and 6% cardiac SSc. The patients had a mean age of 47 years at disease onset, and 16% were men. Diffuse cutaneous SSc was diagnosed in 35% of the subjects, she noted.
Dr. Nihtyanova reported having no disclosures.
SOURCE: Nihtyanova S et al. Arthritis Rheumatol. 2018;70(Suppl 10):