Antiphospholipid syndrome damage index (DIAPS): distinct long-term kinetic in primary antiphospholipid syndrome and antiphospholipid syndrome related to systemic lupus erythematosus

Abstract

Background Antiphospholipid syndrome (APS) is an acquired thrombophilia that affects young productive individuals, with permanent damage and negative impact on quality of life. Recently, a damage index specific for APS (DIAPS) was developed. There are, however, no data regarding the comparison of its performance and long-term damage in primary antiphospholipid syndrome (PAPS) and APS related to systemic lupus erythematosus (SLE; APS + SLE). The primary purpose of this study was therefore to compare the long-term damage in patients with these conditions. Methods This is a retrospective analysis of a single tertiary center cohort followed for approximately 10 years using a standardized prospective electronic chart database. Fifty consecutive PAPS patients age matched with 50 APS+SLE patients were consecutively selected for the study, and DIAPS was calculated once a year during follow-up. Long-term damage and damage kinetics in both groups were compared. Results PAPS and APS + SLE had comparable age (47.10 ± 12.4 vs. 44.04 ± 10.80 years; p = 0.19) and time of follow-up (9.40 ± 3.60 vs. 10.94 ± 4.50 years; p = 0.06). At diagnosis, PAPS had higher DIAPS than APS + SLE (1.72 ± 1.17 vs. 0.82 ± 0.96; p < 0.001). At the end of the 10-year follow-up, both groups presented comparable mean damage scores (2.04 ± 1.50 vs. 2.24 ± 1.61; p = 0.52). The damage increment throughout the observation period for PAPS was solely 35%, whereas for APS + SLE it was gradual, persistent and reached 139% at the end of follow-up, with a total damage increment for PAPS lower than APS + SLE (0.43 ± 0.30 vs. 1.22 ± 1.24; p < 0.001). Of note, the frequency of individuals who acquired damage was lower in PAPS than in APS + SLE (32% vs. 71%; p < 0.001). PAPS also had a longer delay in diagnosis than APS + SLE (4.00 ± 4.20 vs. 2.54 ± 3.05 years; p = 0.04). This delay was positively correlated with a higher damage score at diagnosis ( r = 0.36, p < 0.001) in all groups. Conclusion We identified a distinct pattern of damage in PAPS and APS related to SLE. Damage in PAPS is an early event, while APS+SLE is associated with higher long-term damage, with a striking increment of damage along the follow-up. A diagnosis delay is correlated with higher damage scores. Damage surveillance therefore requires different approaches for these two conditions.