Thrombosis risk with vitamin K antagonists rises more with age than bleeding risk
The risk for bleeding with vitamin K antagonists only increases slightly after age 80 years, but the risk for thrombosis sharply increases, researchers reported in JAMA Internal Medicine.
The researchers analyzed the risk for bleeding and the risk for thrombosis in 1,109 patients aged at least 90 years who were treated at Certe Thrombosis Service Groningen in the Netherlands, between Jan. 21, 2009, and June 30, 2012. Two cohorts were formed: the inception cohort of newly referred patients (n = 385) and the long-term cohort (n = 724). Each patient aged 90 years or older was matched to one patient aged 80 to 89 years and one patient aged 70 to 79 years, for an overall cohort of 3,313 patients (1,394 men). The primary endpoint was a composite of nonmajor and major bleeding. Secondary endpoints included major bleeding, death related to bleeding or thrombosis and thrombotic events.
According to the results, 713 patients (21.5%) had 986 nonmajor and 64 major bleeding events. The event rate per 100 patient-years was 14.8 for patients aged 70 to 79 years, 16.7 for patients aged 80 to 89 years and 18.1 for patients aged at least 90 years. The most common locations of bleeding were skin (31.1%), nose (20.6%), urogenital tract (17.6%) and gastrointestinal tract (16.4%).
Compared with those aged 70 to 79 years, the risk for major bleeding was not significantly higher in patients aged at least 90 years (HR = 1.2; 95% CI, 0.65-2.22) or those aged 80 to 89 years (HR = 1.09; 95% CI, 0.6-1.98). In addition, there was no increase in risk for fatal bleeding in patients aged at least 90 years (HR = 1.32; 95% CI, 0.58-3.01) compared with those aged 70 to 79 years.
A subanalysis revealed that patients in the inception cohort had a higher risk than those in the long-term cohort, and men in both cohorts had a slightly increased risk for bleeding (HR = 1.2; 95% CI, 1.03-1.39) compared with the women.
The researchers also wrote that the risk for developing thrombosis was higher for patients aged at least 90 years (HR = 2.14; 95% CI, 1.22-3.75) compared with those aged 70 to 89 years, and that it was higher for patients aged 80 to 89 years (HR = 1.75; 95% CI, 1.002-3.05) compared with patients aged 70 to 79 years.
“The recommendations to use anticoagulants in patients older than 80 years can be safely extrapolated to the eldest women as well,” they wrote. “The stronger increase in risk of bleeding in the eldest men makes us more cautious to draw final conclusions for this group of patients.” – by Tracey Romero
Disclosure: The researchers report no relevant financial disclosures.