Background/Purpose: AntiPhospholipid Syndrome Alliance For Clinical Trials and InternatiOnal Networking (APS ACTION) is an international research network that has been created specifically to design and conduct well-designed, large-scale, multi-center clinical trials in persistently antiphospholipid antibody (aPL)-positive patients. One of the first needs of APS ACTION was to know the true prevalence of aPL in the general population with pregnancy loss (PrL), stroke (ST), myocardial infarction (MI) and deep venous thrombosis (DVT).
Methods: The search for “aPL” and multiple keywords regarding the outcomes of interest was completed in PubMed; additionally, review articles were searched. A total of 108 full-text papers were collected and analyzed for the type of outcome, the aPL tests used (criteria tests vs.non criteria), the definition of “positive aPL” (low, medium, high, other), the confirmation of aPL (at least 6-12w apart), and the prevalence of positive aPL in the study population (defined by sex and age range). The mean, median, and range of the aPL prevalence were calculated separately for papers with and without aPL confirmation. The incidence of PrL, ST, MI and DVT in the general US population was retrieved from official sources.
Results: Of 108 papers, the outcome of interest was early/late PrL in 32, ST in 31, MI in 24, and DVT in 21. Despite the limitations of the literature, the table demonstrates the estimated prevalence and incidence of aPL-related events. These limitations were: a) approximately 60% of the papers were published between 1984 and 2000; b) the number of aPL criteria tests used was single test in 45 (36.6%), two tests in 65 (52.8%), and 3 tests in 13 (10.6%); c) anticardiolipin and/or anti-β2glycoprotein-I ELISA cut-off was not available in 10% of the papers and “low titer” (<20U) was used in 36% of the papers; d) the method of reporting the cut-off for anti-β2GPI was quite heterogeneous, reflecting the lack of international reference units; e) the confirmation of aPL was performed only in 24 papers (19.5%); and f) half of the studies were not designed to answer our research question (case-control:30%; retrospective cohort/case series:20%).
Conclusion: It is difficult to determine the prevalence of a “clinically significant aPL profile” in the general population patients with pregnancy loss and thrombosis due to the lack of robust data. Pending more rigorous data collection, our best estimates of the incidence of aPL-associated events should be confirmed with appropriately sampled and designed population studies. One of the goals of APS ACTION is to improve upon existing aPL prevalence studies.
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Estimated aPL Prevalence (%) (Literature Review) Mean, Median (Range) |
US Incidence/y * |
Estimated US Incidence/y |
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aPL Confirmation (-) |
aPL Confirmation (+) |
Average (median) |
All Events |
aPL-associated Events |
|
PrL |
12, 9 (0-48) |
14, 14 (0-25) |
12% |
526,000 |
~ 60,000 |
|
ST |
23, 21 (0-49) |
10, 6 (0-53) |
14% |
795,000 |
~ 120,000 |
|
MI |
14, 8 (3-39) |
17, 17 (14-21) |
13% |
935,000 |
~ 120,000 |
|
DVT |
14, 11 (0-35) |
10, 9 (5-19) |
10% |
300,000 |
~ 30,000 |
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* Source: PrL: Macklon N, Hum Reprod Update 2002;8:333; Stephenson MD. Fertil Steril 1996;66:24; National Vital Statistics for the year 2009. ST, MI, DVT: “Heart Disease and Stroke Statistics -2012 Update”, Circulation 2012;125:e12; White RH. Circulation 2003;107:I4; 2010 US Census. |
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Disclosure:
L. Andreoli,
None;
A. Banzato,
None;
C. B. Chighizola,
None;
G. J. Pons-Estel,
None;
G. Ramires de Jesus,
None;
M. D. Lockshin,
None;
D. Erkan,
None;
O. B. O. APS Action,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-estimated-prevalence-of-antiphospholipid-antibodies-in-general-population-patients-with-pregnancy-loss-stroke-myocardial-infarction-and-deep-vein-thrombosis/