EvidenceAlerts

Binding C, Bjerring Olesen J, Abrahamsen B, et al. Osteoporotic Fractures in Patients With Atrial Fibrillation Treated With Conventional Versus Direct Anticoagulants. J Am Coll Cardiol. 2019 Oct 29;74(17):2150-2158. doi: 10.1016/j.jacc.2019.08.1025. (Original study)
Abstract

BACKGROUND: Elderly patients in long-term treatment with vitamin K antagonists (VKAs) are at high risk of osteoporotic fractures compared with the background population. It has been speculated that the choice of oral anticoagulant (OAC) may affect the risk of osteoporotic fractures.

OBJECTIVES: The risk of osteoporotic fractures was evaluated among patients with atrial fibrillation treated with VKA or direct oral anticoagulants (DOACs).

METHODS: Patients were identified using the Danish national registries. Patients were included only if they had no prior use of osteoporosis medication and they had undergone 180 days of OAC treatment. Outcomes were hip fracture, major osteoporotic fracture, any fracture, initiation of osteoporosis medication, and a combined endpoint.

RESULTS: Overall, 37,350 patients were included. The standardized absolute 2-year risk of any fracture was low among DOAC-treated patients (3.1%; 95% CI: 2.9% to 3.3%) and among VKA-treated patients (3.8%; 95% CI: 3.4% to 4.2%). DOAC was associated with a significantly lower relative risk of any fracture (hazard ratio [HR]: 0.85; 95% CI: 0.74 to 0.97), major osteoporotic fractures (HR: 0.85; 95% CI: 0.72 to 0.99), and initiating osteoporotic medication (HR: 0.82; 95% CI: 0.71 to 0.95). A combined endpoint showed that patients treated with DOAC had a significantly lower relative risk of experiencing any fracture or initiating osteoporosis medication (HR: 0.84; 95% CI: 0.76 to 0.93).

CONCLUSIONS: In a nationwide population, the absolute risk of osteoporotic fractures was low among patients with atrial fibrillation on OAC, but DOAC was associated with a significantly lower risk of osteoporotic fractures compared with VKA.

Ratings
Discipline Area Score
Family Medicine (FM)/General Practice (GP) 7 / 7
General Internal Medicine-Primary Care(US) 7 / 7
Cardiology 6 / 7
Endocrine 6 / 7
Hemostasis and Thrombosis 6 / 7
Internal Medicine 5 / 7
Comments from MORE raters

General Internal Medicine-Primary Care(US) rater

A very interesting finding that is relevant to primary care practice where anticoagulation therapy is usually initiated in patients with afib. Although small, the result showed another advantage of NOACs over vitamin K antagonist agents. In patients who are already at high risk for osteoporosis, however, placing them on an NOAC vs warfarin may make a difference.

Hemostasis and Thrombosis rater

This is very important information that adds to the reasons why patients who are newly starting anticoagulant medication to reduce the risk for stroke in AF may prefer a DOAC over a VKA.

Hemostasis and Thrombosis rater

This is a very provocative article associating VKA with bone loss. This has been a theoretical concern (bone has vit k dependent proteins) but the article provides more credence for this idea. This is more evidence that DOACs are the preferred agent for those who can take them.

Hemostasis and Thrombosis rater

This is a large-scale cohort using data gleaned from a reliable comprehensive national health system (Denmark). Although "retrospective," the methods are sufficiently sound to allow clinicians to use the data for making clinical decisions. The data support the long-held suspicion that VKA drugs may enhance osteoporosis risk with a clinically significant higher fracture rate. These data are important and another consideration to add to the complex question of which anticoagulant to select for individualized care of a given patient.

Internal Medicine rater

The differences are modest and might be due to confounding.

Internal Medicine rater

More support for DOACs over VKAs if the patient does not have a valve replacement.
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