Associated factors of antiphospholipid syndrome. When do we need antiphospholipid antibodies?

Abstract

Introduction

In clinical practice, there is no specific recommendation on when to take samples in case of clinical suspicion of antiphospholipid syndrome, only a list of factors that generate APS risk, without adequately quantifying the weight of each of these factors.

Materials and methods

Analytical observational case-control study, nested in a retrospective cohort of patients with venous or arterial thrombosis in whom antiphospholipid syndrome was clinically suspected. Patients with a confirmed diagnosis of antiphospholipid syndrome according to the Sapporo criteria or triple positive initial result (cases) are compared with patients negative for APS (controls). The association between the diagnosis of APS and different clinical and paraclinical factors was evaluated.

Results

68 patients were included (72% women, 41.2% with deep venous thromboembolism and 29.4% with pulmonary embolism). In 18 SAF was confirmed. There were no significant differences in age in patients with and without confirmation of the diagnosis (44.0±17.9 vs. 51.2±14.9, p = 0.069). In the multivariate analysis, a significant and independent association was found between having APS and rheumatic disease (OR 12.1, p = 0.02), PTT prolongation (OR 17.6, p = 0.014), platelet count < 150000 (OR 18.6, p = 0.008), and a history of previous thrombosis events (OR: 6.1 for each event, p = 0.027).

Conclusions

In patients with arterial or venous thrombosis, there is a greater possibility of confirming antiphospholipid syndrome if there is a history of rheumatic disease, prolongation of PTT to more than 5 seconds, thrombocytopenia, and previous events of thrombotic disease. In these patients it is advisable to search for APS, in order to prevent new events.