Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Antiphospholipid Score (aPL-S): A Comprehensive Predictive Marker of Developing Thrombosis in Autoimmune Diseases.

Otomo1,  Kotaro, Atsumi2,  Tatsuya, Fujieda3,  Yuichiro, Kato3,  Masaru, Amengual3,  Olga, Horita3,  Tetsuya, Yasuda3,  Shinsuke

Hokkaido Graduate School of Medicine, Department of Medicine II, Sapporo, Hokkaido, Japan
Hokkaido Graduate School of Medicine, Department of Medicine II, Sapporo, Japan
Hokkaido Graduate School of Medicine, Department of Medicine II

Objective:

We have previously defined the Antiphospholipid Score (aPL-S) by testing multiple antiphospholipid antibodies (aPL), and evaluated its efficacy for the diagnosis of antiphospholipid syndrome (APS) as well as its predictive value for the development of thrombotic events in patients with autoimmune diseases (Presentation Number 1216 in ACR 2009). In the present study, we further analyzed the associated-risk of thrombosis for each aPL assay in autoimmune diseases. Further, we investigated the relationship between the aPL-S and each single aPL test.

Patients and Methods:

This study comprised 411 patients with autoimmune diseases who visited our Rheumatic and Connective Tissue Disease Department. Between 2002 and 2003, five Lupus Anticoagulant (LAC) assays (the mixing studies: activated partial thromboplastin time (APTT), kaolin clotting time, the dilute Russel's viper venom test (dRVVT), and the confirmatory tests: APTT and dRVVT) and 6 ELISAs (IgG/M anticardiolipin (aCL) antibodies, IgG/M anti-beta2-glycoprotein I (ab2GPI) antibodies and IgG/M phosphatidylserine dependent antiprothrombin (aPS/PT) antibodies) were performed in all subjects. Among all the patients, 296 (72.0%) were followed-up with a mean duration of 67 ±15 months. The disease profile of these patients was as follows; 17(6%) primary APS, 26(9%) APS associated with other autoimmune disease, 89(29%) SLE (without APS), 50(17%) rheumatoid arthritis and 114 patients with several other autoimmune diseases. To evaluate the predictive value of thrombosis for each aPL-analyzed test, positive results in each assay were contrasted with the presence of new thrombotic events during the follow-up period.

Results:

Thirty-two patients newly developed thromboses during the observation period; 22 arterial thromboses and 14 venous thromboses.

Patients with either positive LAC or IgG aPS/PT had a stronger risk of thrombosis than those without. The odds ratio (OR [95%CI]) associated to each test was 3.26 [1.55–6.90, p=0.001] and 4.80 [2.03–11.04, p=0.0001], respectively. The OR values in patients with aPL-S more than 10, 30 and 50 were 2.86 [1.33–6.16, p=0.006], 5.27 [2.32–11.95, p<0.0001] and 5.31 [1.81–15.53, p=0.0008], respectively. Thus, the positive predictive values of aPL-S more than 30 and 50 were higher than any other value of each single aPL test (see figure.). The negative predictive values of aPL-S, LAC and IgG aPS/PT were within the similar levels (90.7–92.9%).

Conclusion:

The aPL-S may be a useful comprehensive quantitative marker for predicting thrombosis in autoimmune diseases.

To cite this abstract, please use the following information:
Otomo, Kotaro, Atsumi, Tatsuya, Fujieda, Yuichiro, Kato, Masaru, Amengual, Olga, Horita, Tetsuya, et al; Antiphospholipid Score (aPL-S): A Comprehensive Predictive Marker of Developing Thrombosis in Autoimmune Diseases. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :5
DOI: 10.1002/art.27775

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