RECURRENT VENOUS THROMBOEMBOLISM

Men are at greater risk.

Men and women both are more likely to have a venous thromboembolism as they age (either deep-vein thrombosis or a pulmonary embolism), but the distribution of thrombotic events by sex is not the same in all age groups-women of childbearing age are more likely than men of comparable age, for example, to suffer from a first thromboembolism. The overall recurrence rate is 5% to 10% per year, but that rate is higher among older men, compared with older women.

In an ongoing prospective study in Vienna, 826 patients have been followed for two years after the completion of anticoagulation therapy for a first venous thromboembolism. Patients at very high risk who needed continued anticoagulation therapy because of factors such as the incidence of more than one previous thromboembolism, cancer, arterial disease, or atrial fibrillation were not included.

The mean age at which a first thromboembolism occurred in women was only 45. Pregnancy, the use of oral contraceptives, and hormone replacement therapy are factors associated with it-one-third of the women in the study experienced a first thromboembolism while taking oral contraceptives. Hormone replacement therapy has been found to double the risk of the incidence of a first thrombosis. Despite the greater risk of an initial thromboembolic event occurring among women taking oral contraceptives or hormone replacement therapy, there was the same rate of recurrence among them as there was among other women, possibly, in part, because the study authors emphatically advised them to discontinue the use of both. Women to whom oral contraceptives or hormone replacement therapy are prescribed should be warned of the greater risk of thrombosis.

Among men, the mean age at first venous thromboembolism was 51, six years older than it was among women.

Two years after the initial thrombosis, elevated levels of factor VIII, symptomatic pulmonary embolism as the first thromboembolic event, and advancing age all were risk factors in recurrent thromboembolism, but sex was the most significant determinant of it-20% of the men, but only 6% of the women, suffered from a recurrence. The risk among men was more than three and a half times that among women, and remained so after five years.

It's not known why that recurrence rate among men is so much higher than it is among women-more research into risk factors present in men is necessary, as is inquiry into possible protective factors in older women. The ongoing risk of recurrence among women should not be minimized, however, and more study is necessary before any change in the duration of secondary thromboprophylaxis used in women is considered. -FM

Kyrle PA, et al. N Engl J Med 2004; 350(25):2558-63.

BLOOD GLUCOSE UPON ADMISSION AFTER AMI

A high level signals a greater long-term risk of death.

The presence of an elevated blood glucose level (200 mg/dL or higher) when hospitalized after acute myocardial infarction (AMI) is independently predictive of a greater long-term risk of death in patients both with and without diabetes.

In a retrospective study, 846 patients (n = 737 without diabetes, n = 109 with it) admitted with AMI to the coronary care unit of a hospital in the Netherlands between 1989 and 1996 were prospectively followed for a median of 50 months to determine the relationship between blood glucose level at admission after AMI and the long-term risk of death.

The results showed that significantly more patients with known diabetes died (43.1%), compared with those without it (28.2%). An increase in blood glucose level of 18 mg/dL (1 mmol/L) in patients without diabetes was associated with a 4% greater risk of death (there was a 5% greater risk of it in patients with known disease). Nearly 14% of patients without diabetes had blood glucose levels of 200 mg/dL (11.1 mmol/L) or higher at admission, and the mortality rate among them was both significantly higher (42.6%) than that among patients with blood glucose levels lower than 200 mg/dL and comparable to that among those with known diabetes (43.1%). Additionally, there was a greater incidence of congestive heart failure while hospitalized among patients without known diabetes but with blood glucose levels of 200 mg/dL or higher at admission, compared with patients without known disease who had blood glucose levels lower than 200 mg/dL.

Patients without diabetes hospitalized after AMI and with blood glucose levels of 200 mg/dL or higher should be assessed for other risk factors associated with diabetes and followed up, because the long-term mortality risks among them are comparable to that among those with the disease. -JC

Stranders I, et al. Arch Intern Med 2004; 164(9):982-8.