Observation versus antiplatelet therapy as primary prophylaxis for thrombosis in low-risk essential thrombocythemia.
The effectiveness of antiplatelet therapy as primary prophylaxis for thrombosis in low-risk essential thrombocythemia (ET) is not proven. In this study, the incidence rates of arterial and venous thrombosis were retrospectively analyzed in 300 low-risk patients with ET treated with antiplatelet drugs as monotherapy (n = 198) or followed with careful observation (n = 102). Follow-up was 802 and 848 person-years for antiplatelet therapy and observation, respectively. Rates of thrombotic events were 21.2 and 17.7 per 1000 person-years for antiplatelet therapy and observation, respectively (P = .6). JAK2 V617F-positive patients not receiving antiplatelet medication showed an increased risk of venous thrombosis (incidence rate ratio [IRR]: 4.0; 95% CI: 1.2-12.9; P = .02). Patients with cardiovascular risk factors had increased rates of arterial thrombosis while on observation (IRR: 2.5; 95% CI: 1.02-6.1; P = .047). An increased risk of major bleeding was observed in patients with platelet count greater than 1000 x 10(9)/L under antiplatelet therapy (IRR: 5.4; 95% CI: 1.7-17.2; P = .004). In conclusion, antiplatelet therapy reduces the incidence of venous thrombosis in patients with JAK2-positive ET and the rate of arterial thrombosis in patients with associated cardiovascular risk factors. In the remaining low-risk patients, this therapy is not effective as primary prophylaxis of thrombosis, and observation may be an adequate option.
Alvarez-Larrán
Alberto
A
Hematology Department, Hospital del Mar, Barcelona, Spain. 95967@parcdesalutmar.cat
Cervantes
Francisco
F
Pereira
Arturo
A
Arellano-Rodrigo
Eduardo
E
Pérez-Andreu
Virginia
V
Hernández-Boluda
Juan-Carlos
JC
Ayats
Ramón
R
Salvador
Carlos
C
Muntañola
Ana
A
Bellosillo
Beatriz
B
Vicente
Vicente
V
Hernández-Nieto
Luis
L
Burgaleta
Carmen
C
Xicoy
Blanca
B
Besses
Carlos
C
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D010976:Platelet Count; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D013920:Thrombocythemia, Essential / Q000150:complications* / Q000628:therapy; D013927:Thrombosis / Q000209:etiology* / Q000517:prevention & control*; D016896:Treatment Outcome; D055815:Young Adult
D010975:Platelet Aggregation Inhibitors