Persistent low-moderate thrombocytopenia may help identify high risk for thrombosis, poor long-term survival, and predict thrombosis-linked mortality in patients with antiphospholipid syndrome (APS), according to study results published in Rheumatology.
Thrombocytopenia is often associated with antiphospholipid (aPL) antibodies. Previous studies have not found evidence of an association between APS and bleeding; however, the clinical importance of thrombosis in APS still remains unclear.
A team of researchers conducted a study to evaluate thrombocytopenia and other clinical variables as possible predictors for outcomes in patients with APS. They used data from a large cohort of patients with APS who were assessed in a 38-year follow-up.
A total of 114 patients (mean age, 38±15 years; 66% women) were included in the analysis; 73 (64%) had primary APS, 29 (25%) had secondary APS, and 12 (10%) were asymptomatic but tested positive for aPL antibodies. Mean follow-up was 19 years (2202 person-years). Of the 87% of patients (n=100) who experienced thrombotic events, 51% had venous events, 38% had arterial events, and 11% had microvascular events.
One-quarter of the study cohort (n=29) had thrombocytopenia, including 23 patients with the persistent form. A total of 35 (30%) patients died. The main causes of death were neoplasia (n=8) and infection (n=8). Of the reported deaths, thrombosis was the cause of 13% and 1% of mortalities among patients with and without thrombocytopenia (P =.01), respectively.
Although Cox-regression models indicated that positive antinuclear antibodies, arterial thrombotic events, myocardial infarction, intracardiac thrombosis, and thrombocytopenia were risk factors for all-cause mortality, results from multivariate analysis were only significant for thrombocytopenia (hazard ratio [HR], 2.7; 95% CI, 1.3-6.0; P =.01).
Compared with acute and severe forms, persistent (HR, 4.4; 95% CI, 2.1-9.2; P =.001) and low-moderate thrombocytopenia (HR, 2.8; 95% CI, 1.2-6.4; P =.01) were both significantly associated with an increase in mortality. Patients with APS and thrombocytopenia were more often men, had arterial thrombosis, had lupus anticoagulant positivity, type I antiphospholipid antibody profile, and underwent anticoagulant treatment.
One of the main study limitations included the lack of information on specific causes of thrombocytopenia.
“Persistent mild-moderate thrombocytopenia is associated with a reduced long-term survival in APS and should be considered a relevant risk factor to stratify patients,” the researchers noted. “It should also be taken into account in the design of studies on disease pathogenesis and therapeutic strategies as well as in revisions to the current APS classification criteria.”
Pardos-Gea J, Marques-Soares JR, Buján S, Ordi-Ros J, Alijotas-Reig J. Persistent thrombocytopenia predicts poor long-term survival in patients with antiphospholipid syndrome: a 38-year follow-up study. Rheumatology. Published online June 11, 2021 doi:10.1093/rheumatology/keab475