Clinical Edge

Summaries of Must-Read Clinical Literature, Guidelines, and FDA Actions

Vitamin K Antagonist Use in Older Patients

JAMA Intern Med; ePub 2016 Aug; Kooistra, et al

While the bleeding risk with a vitamin K antagonist (VKA) only mildly increases in patients aged >80 years, there is a significant increase in the risk of thrombosis in the same age group, a recent study found. The matched cohort study included 3,313 patients who were treated with a VKA between January 21, 2009 and June 30, 2012. All 1,109 patients ≥90 years who were treated with a VKA were randomly matched 1:1:1 with 1,100 patients aged 80 to 89 years and 1,104 patients aged 70 to 79 years based on duration of VKA treatment. Researchers found:

  • During 6,419 observation-years, 713 patients had 1,050 bleeding events.

  • Risk of bleeding was not significantly increased in patients aged 80 to 89 years and mildly increased in patients ≥90 years compared with patients aged 70 to 79 years.

  • The point estimates for major bleeding were comparable for patients aged 80 to 89 years and those ≥90 years compared with those aged 70 to 79 years.

  • The increase in bleeding risk was sharper in men than in women.

  • 85 patients (2.6%) developed a thrombotic event; risk was higher in patients in their 90s.


Kooistra HM, Calf AH, Piersma-Wichers M, et al. Risk of bleeding and thrombosis in patients 70 years or older using vitamin K antagonists. JAMA Intern Med. 2016;176(8):1176-1183. doi:10.1001/jamainternmed.2016.3057.


The risk of stroke secondary to atrial fibrillation increases with age, as does the risk of bleeding on warfarin. To obtain information on this group of patients who are often not included in randomized trials, the authors used a “real-world” design, looking at a cohort of patients in their 70’s, 80’s and 90’s. This study suggests that while we still need to be careful in weighing the risk and benefit of anticoagulation decisions in the elderly, the risk of bleeding does not continue to dramatically increase from age 70 to 90, while the risk of thrombosis continues to increase. It is important to recognize that decisions about anticoagulation have to be carefully individualized and that population data such as those described in this study can help us to understand general risk, but the decisions we make for individual patients have to be based on their particular set of circumstances, which influence both benefit and risk. —Neil Skolnik, MD