Table 1. Studies addressing primary... | American Society of Hematology

Table 1.

Studies addressing primary prophylaxis in asymptomatic patients with antiphospholipid antibodies.

Author, year	Study design	N	Number of aPL measurements	Comparison/ intervention	Results/conclusions
AIT indicates autoimmune thrombocytopenia; aPL, antiphospholipid antibodies; ASA, aspirin; CI, confidence interval; CTD, connective tissue disease; HCQ, hydroxychloroquine; HR, hazard ratio; LMWH, low molecular weight heparin; N/A, not available; OR, odds ratio; RCT, randomized controlled trial; SLE, systemic lupus erythematosus; TIA, transient ischemic attack.
*Enoxaparin 1 mg/kg once daily for surgery or immobilization; ASA 325 mg/d during pregnancy; both in combination with counseling and treatment to reduce vascular risk factors
**52/81 patients received primary prophylaxis (ASA = 50, oral anticoagulants = 1, clopidogrel = 1)
*Asymptomatic aPL patients*
Hereng et al, 2008⁵	Retrospective	103	2; Unknown time interval between measurements	ASA (n = 75) vs Observation (n = 28)	-Lower frequency of thrombotic events in ASA group, especially in the subgroup of patients with SLE or AIT -36% of patients had SLE
Erkan et al, 2007³	RCT with parallel prospective cohort	RCT: 98  Cohort: 74	≥ 2; 6 weeks apart	RCT: ASA 81 mg daily (n = 48) vs  Placebo (n = 50)  Cohort: ASA (n = 61)	-HR: 1.04 (95% CI 0.69–1.56) -> 60% of patients in RCT had SLE -ASA not effective in preventing thrombosis compared to placebo
Giron-Gonzalez et al, 2004¹⁰	Prospective	178	≥ 2; 8–12 weeks apart	ASA 325 mg/d or LMWH daily during high risk situations*	-All patients received thromboprophylaxis during high risk situations, no thrombotic events occurred
Erkan et al, 2002⁹	Cross-sectional	56	Not specified	Logistic regression analysis (ASA and/or HCQ use)	-Probability of thrombotic event decreased in patients taking ASA +/− HCQ (HCQ only in patients with CTD) -78% of patients had CTD
*SLE patients*
Tektonidou et al, 2009⁷	Retrospective	288; 144 aPL positive	≥ 2; ≥ 12 weeks apart	Adjusted survival analysis (ASA 80–100 mg/d, HCQ)	-HR per month: ASA 0.98 (95% CI 0.96–0.99) and HCQ 0.99 (95% CI 0.98–1.00) -Duration of use of ASA and HCQ associated with decreased thrombosis
Kaiser et al, 2009⁶	Retrospective	1930; 516 aPL positive	1	Logistic regression analysis (HCQ use)	-OR 0.63 (95% CI 0.48–0.83) -HCQ protective against thrombosis
Tarr et al, 2007⁴^,⁸	Prospective	272; 81 aPL positive	≥ 2; 6 weeks apart	Prophylaxis (n = 52) vs Observation (n = 29)**	-Lower incidence of thrombosis in prophylaxis group vs observation group (1/52 vs 2/29 had stroke or TIA)

Author, year	Study design	N	Number of aPL measurements	Comparison/ intervention	Results/conclusions
AIT indicates autoimmune thrombocytopenia; aPL, antiphospholipid antibodies; ASA, aspirin; CI, confidence interval; CTD, connective tissue disease; HCQ, hydroxychloroquine; HR, hazard ratio; LMWH, low molecular weight heparin; N/A, not available; OR, odds ratio; RCT, randomized controlled trial; SLE, systemic lupus erythematosus; TIA, transient ischemic attack.
*Enoxaparin 1 mg/kg once daily for surgery or immobilization; ASA 325 mg/d during pregnancy; both in combination with counseling and treatment to reduce vascular risk factors
**52/81 patients received primary prophylaxis (ASA = 50, oral anticoagulants = 1, clopidogrel = 1)
*Asymptomatic aPL patients*
Hereng et al, 2008⁵	Retrospective	103	2; Unknown time interval between measurements	ASA (n = 75) vs Observation (n = 28)	-Lower frequency of thrombotic events in ASA group, especially in the subgroup of patients with SLE or AIT -36% of patients had SLE
Erkan et al, 2007³	RCT with parallel prospective cohort	RCT: 98  Cohort: 74	≥ 2; 6 weeks apart	RCT: ASA 81 mg daily (n = 48) vs  Placebo (n = 50)  Cohort: ASA (n = 61)	-HR: 1.04 (95% CI 0.69–1.56) -> 60% of patients in RCT had SLE -ASA not effective in preventing thrombosis compared to placebo
Giron-Gonzalez et al, 2004¹⁰	Prospective	178	≥ 2; 8–12 weeks apart	ASA 325 mg/d or LMWH daily during high risk situations*	-All patients received thromboprophylaxis during high risk situations, no thrombotic events occurred
Erkan et al, 2002⁹	Cross-sectional	56	Not specified	Logistic regression analysis (ASA and/or HCQ use)	-Probability of thrombotic event decreased in patients taking ASA +/− HCQ (HCQ only in patients with CTD) -78% of patients had CTD
*SLE patients*
Tektonidou et al, 2009⁷	Retrospective	288; 144 aPL positive	≥ 2; ≥ 12 weeks apart	Adjusted survival analysis (ASA 80–100 mg/d, HCQ)	-HR per month: ASA 0.98 (95% CI 0.96–0.99) and HCQ 0.99 (95% CI 0.98–1.00) -Duration of use of ASA and HCQ associated with decreased thrombosis
Kaiser et al, 2009⁶	Retrospective	1930; 516 aPL positive	1	Logistic regression analysis (HCQ use)	-OR 0.63 (95% CI 0.48–0.83) -HCQ protective against thrombosis
Tarr et al, 2007⁴^,⁸	Prospective	272; 81 aPL positive	≥ 2; 6 weeks apart	Prophylaxis (n = 52) vs Observation (n = 29)**	-Lower incidence of thrombosis in prophylaxis group vs observation group (1/52 vs 2/29 had stroke or TIA)