To determine the association between serum autoantibodies and survival in patients with incident systemic sclerosis (SSc)-pulmonary arterial hypertension (PAH) enrolled in the Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma (PHAROS) Registry.
Patients with definite PAH diagnosed by right heart catheterization within 6 months of registry enrollment were studied. Serum autoantibodies were assayed at each participating institution's clinical laboratory. Mortality data were collected from electronic medical records and/or the Social Security Death Index. Kaplan-Meier survival estimates were reported for five autoantibody groups (anticentromere/AC, nucleolar ANA/NUC, anti-topoisomerase/Scl-70, overlapping or non-specific autoantibodies/other, and a combined group with similar survival consisting of RNA polymerase III, U1RNP, and autoantibody-negative patients). Cox proportional hazards models permitted examination of the association between autoantibody groups and overall survival, controlling for age, sex, race, and SSc disease duration.
In all, 162 subjects had PAH, and serum autoantibody and survival information; 60 (37%) had AC, 39 (24%) NUC, 11 (7%) Scl-70, 28 (17%) had other, 9 (6%) RNA pol, 8 (5%) U1RNP autoantibodies, and 7 (4%) had negative antibodies; 32 (20%) subjects died over a median follow-up time of 2.1 years (range: 0.01-6.8); 1- and 3-year survival estimates were, respectively, 94% and 78% for AC, 94% and 72% for NUC, 89% and 63% for Scl-70, 92% and 79% for the other group, and 100% and 93% for the combined group. Unadjusted and adjusted hazard ratios revealed no statistically significant association between risk of death and autoantibodies.
Anticentromere and NUC autoantibodies are prevalent in SSc-PAH patients. An association between serum autoantibodies and survival in patients with SSc-PAH was not identified in the PHAROS cohort.