Efficacy and safety of low-dose aspirin in polycythemia vera.
BACKGROUND
The use of aspirin for the prevention of thrombotic complications in polycythemia vera is controversial.


METHODS
We enrolled 518 patients with polycythemia vera, no clear indication for aspirin treatment, and no contraindication to such treatment in a double-blind, placebo-controlled, randomized trial to assess the safety and efficacy of prophylaxis with low-dose aspirin (100 mg daily). The two primary end points were the cumulative rate of nonfatal myocardial infarction, nonfatal stroke, or death from cardiovascular causes and the cumulative rate of nonfatal myocardial infarction, nonfatal stroke, pulmonary embolism, major venous thrombosis, or death from cardiovascular causes. The mean duration of follow-up was about three years.


RESULTS
Treatment with aspirin, as compared with placebo, reduced the risk of the combined end point of nonfatal myocardial infarction, nonfatal stroke, or death from cardiovascular causes (relative risk, 0.41; 95 percent confidence interval, 0.15 to 1.15; P=0.09) and the risk of the combined end point of nonfatal myocardial infarction, nonfatal stroke, pulmonary embolism, major venous thrombosis, or death from cardiovascular causes (relative risk, 0.40; 95 percent confidence interval, 0.18 to 0.91; P=0.03). Overall mortality and cardiovascular mortality were not reduced significantly. The incidence of major bleeding episodes was not significantly increased in the aspirin group (relative risk, 1.62; 95 percent confidence interval, 0.27 to 9.71).


CONCLUSIONS
Low-dose aspirin can safely prevent thrombotic complications in patients with polycythemia vera who have no contraindications to such treatment.
Landolfi
Raffaele
R
Catholic University School of Medicine, Rome, Italy. rlandolfi@rm.unicatt.it
Marchioli
Roberto
R
Kutti
Jack
J
Gisslinger
Heinz
H
Tognoni
Gianni
G
Patrono
Carlo
C
Barbui
Tiziano
T
D001241:Aspirin / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000401:mortality; D018572:Disease-Free Survival; D004311:Double-Blind Method; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D011087:Polycythemia Vera / Q000150:complications* / Q000188:drug therapy; D012307:Risk Factors; D013927:Thrombosis / Q000209:etiology / Q000517:prevention & control*
D010975:Platelet Aggregation Inhibitors; D001241:Aspirin