Thrombosis in systemic lupus erythematosus: the role of antiphospholipid antibody

Increased risk of subarachnoid hemorrhage in patients with systemic lupus erythematosus: a nationwide population-based study

OBJECTIVE

A relatively common occurrence of spontaneous subarachnoid hemorrhage (SAH) in patients with systemic lupus erythematosus (SLE) has been noted; however, the subsequent studies were conflicting. This nationwide population-based study aimed to evaluate the risk of SAH in patients with SLE.

METHODS

We identified 16,967 SLE patients from the Taiwan National Health Insurance (NHI) database between 2000 and 2006, and compared the incidence rate of SAH with 16,967 randomly selected age- and sex-matched non-SLE subjects. A Cox multivariable proportional hazards model was used to evaluate the risk factors of SAH in the SLE cohort.

RESULTS

The SLE cohort had a higher risk of SAH, with an incidence rate ratio of 4.84 (P < 0.001). Despite a younger age, the mortality rate after SAH was significantly higher in the SLE cohort compared to all of the non-SLE SAH patients identified from the 1 million NHI beneficiaries (60.0% versus 38.9%; P = 0.007). Age (hazard ratio [HR] 1.03, 95% confidence interval [95% CI] 1.01-1.05), platelet transfusion (HR 2.75, 95% CI 1.46-5.17), red blood cell transfusion (HR 7.11, 95% CI 2.81-17.97), and a mean daily steroid dose >10 mg of prednisolone or equivalent (HR 4.36, 95% CI 2.19-8.68) were independent risk factors for the new onset of SAH.

CONCLUSION

This study demonstrated that SAH is a rare but associated complication of SLE with a high mortality rate. Other than age, higher mean daily steroid use and a history of platelet or red blood cell transfusion were associated with the occurrence of SAH in patients with SLE.

Thrombosis in systemic lupus erythematosus: congenital and acquired risk factors

OBJECTIVE

To investigate the thrombotic tendency in patients with systemic lupus erythematosus (SLE) by evaluating congenital or acquired abnormalities associated with an increased risk of venous and/or arterial thrombosis.

METHODS

A total of 57 patients with SLE were included in the study. Twenty-one patients (37%) had a history of arterial and/or venous thrombosis and 36 patients (63%) did not have such a history. Sera from 50 healthy controls were examined. Protein C, protein S, antithrombin, D-dimer, fibrinogen, homocysteine, anticardiolipin antibodies (aCL), lupus anticoagulant (LAC), prothrombin G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T gene mutation were evaluated.

RESULTS

Protein C, antithrombin, fibrinogen, D-dimer, and homocysteine levels were significantly higher in patients with SLE than in controls. A prothrombin mutation was observed in 2 (4%) of 50 controls and in 6 (11%) of 57 patients. A significantly higher prevalence (P = 0.036) of MTHFR homozygous mutation was observed in patients with SLE (14 [25%] of 57) in comparison with controls (4 [8%] of 50). IgG-aCL and IgM-aCL levels were significantly higher in patients with SLE than in controls (P < 0.0001). The presence of medium-high (> or = 20 IgG phospholipid units/ml) IgG-aCL antibody titers was significantly higher (P = 0.005) in patients with thrombosis (11 [52%] of 21) than in patients without (5 [14%] of 36) thrombosis. LAC was present in 22 (38.5%) of 57 patients and in none of 50 controls.

CONCLUSION

In this study, we confirm the association between thrombosis and IgG-aCL at medium-high titers and suggest that the coexistence of other risk factors can affect the expression of thrombosis in patients with SLE.

Antiphospholipid antibody tests: spreading the net

OBJECTIVE

To examine the hypothesis that testing for new antiphospholipid antibody specificities may help to identify the antiphospholipid syndrome (APS) in patients with systemic lupus erythematosus (SLE) with thrombosis who are repeatedly negative for anticardiolipin antibodies (aCL) and/or lupus anticoagulant (LA).

METHODS

Three groups of patients with SLE were studied: (a) SLE/APS (n = 56): 51 female, mean (SD) age 46 (11) years, fulfilling 1999 Sapporo criteria for the APS; (b) SLE/thrombosis (n = 56): 53 female, age 42.6 (12) years, all with a history of thrombosis and persistently negative for aCL and/or LA; (c) SLE only (n = 56): 53 female, age 40 (11) years, without a history of thrombotic events. aCL and LA were retested in all samples. All patients were tested for anti-beta(2)-glycoprotein I (anti-beta(2)GPI) and antiprothrombin antibodies (aPT) by coating prothrombin on irradiated plates or using phosphatidylserine-prothrombin complex as the antigen (aPS-PT).

RESULTS

Anti-beta(2)GPI were only present in patients from the SLE/APS group, all of whom were also positive for aCL. aPT and aPS-PT were also more commonly found in SLE/APS than in SLE/thrombosis or SLE only groups (54% v 5%, p<0.0001 or v 16%, p<0.0001 for aPT and 63% v 2%, p<0.0001 or v 11%, p<0.0001 for aPS-PT, respectively). No differences were found between SLE/thrombosis and SLE only groups (p = 1.5 for beta(2)GPI, p = 0.1 for aPT, and p = 0.1 for aPS-PT).

CONCLUSION

Testing for aPT in patients with SLE with thrombosis, but persistently negative for aCL and LA, may be helpful in some selected cases. Anti-beta(2)GPI are not present in patients who are negative for aCL.

Clinical importance of positive test results for lupus anticoagulant and anticardiolipin antibodies

OBJECTIVES

To assess the performance of 4 clotting assays for lupus anticoagulant (LA) detection, to determine the prevalence of LA and anticardiolipin antibodies (aCL), and to correlate LA and aCL prevalence with systemic disease and thrombosis.

PATIENTS AND METHODS

We studied 664 consecutive patients at the Mayo Clinic in Rochester, Minn, who were referred for laboratory testing because of a clinical suspicion of LA or thrombophilia between June 25, 1990, and July 1, 1991.

RESULTS

Of 664 patients tested for LA, 584 also were tested for aCL. Of patients tested for both LA and aCL, 137 (235%) had positive results for one or both tests (13 [95%], LA-positive only; 76 [555%], aCL-positive only; and 48 [35.0%], positive for both). The dilute Russell viper venom time (DRVVT) was the most frequently positive LA assay (74% of the 61 patients with positive results for LA). Twenty-two patients (36.1% of the 61) had positive results for all 4 LA assays, whereas 21 (34.4% of the 61) had positive results for only 1 LA assay: activated partial thromboplastin time (3 patients [4.9%]), plasma clot time (5 patients [8.2%]), kaolin clot time (5 patients [8.2%]), or DRVVT (8 patients [13.1%]). Thromboembolism prevalence was not definitely associated with positive test results (LA only, aCL only, or LA plus aCL), nor was it strongly associated with aCL isotype or titer. Furthermore, thromboembolism prevalence was not increased when all LA assays were positive, although a history of deep venous thrombosis or pulmonary embolism was nonsignificantly associated with positive results for all 4 LA tests. The likelihood of having both LA- and aCL-positive test results was higher among patients with systemic lupus erythematosus (26 [19.0%] of 137 patients with positive results for one or both tests), but they had no more thrombotic events or fetal loss than other patients in our study group.

CONCLUSIONS

The DRVVT identified more patients with LA than the other LA tests, but more than 1 LA test was required to identify all patients with LA. Positive results were much more common for aCL than for LA. No single LA test or anticardiolipin isotype correlated with thrombosis or systemic disease in this population.