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Nearly half of patients receiving anticoagulation fail to reach minimum quality of therapy
Many patients assigned anticoagulants fail to reach the minimum time in therapeutic range to benefit from the therapy, researchers in Spain found through an observational study.
Kidney disease and elevated risk for cerebral hemorrhage were linked to diminished control, with different approaches to estimate time spent in range demonstrating comparable capability.
“In the ANFAGAL study, more than 40% of patients on anticoagulants do not reach the minimum quality of anticoagulation,” the researchers wrote. “The method for assessing [time in therapeutic range] by counting the number of acceptable controls is as effective as the Rosendaal method, which is more tedious and often requires use of a computer.”
Sergio Cinza-Sanjurjo, MD, of the Centro de Salud de Porto do Son, Xerencia de Xestión Integrada, Santiago de Compostela, A Coruña, Spain, and colleagues looked at 511 patients (53% women; mean age, 77.8 years) with nonvalvular atrial fibrillation who were assigned anticoagulants for at least 1 year. Patients were from primary care clinics in Galicia, Spain.
The investigators defined control as good when the time spent in therapeutic range was more than 65% based on the Rosendaal method or more than 60% based on the number of acceptable controls.
In the analyzed period, 42.7% of patients spent less than 65% of time in therapeutic range using the Rosendaal estimation method, and 41.5% of patients were within range in fewer than 60% of acceptable controls.
Among patients with poor control, the researchers observed more drug use (6.8 vs. 5.7; P < .0001), higher incidence of kidney disease (24.3% vs. 17%; P = .05) and elevated HAS-BLED scores (3.8 vs. 2.5; P < .0001).
The 60% cut point for number of acceptable controls had a sensitivity of 79.4% and specificity of 86.7%, and the area under the curve was 0.92 (95% CI, 0.87-0.97).
“We observed that patients at greater risk of bleeding also had poorer control,” the researchers wrote. “This finding has almost immediate implications in clinical practice, because these patients are the ones who most stand to benefit from the use of the new oral anticoagulants.” – by Allegra Tiver
Disclosure: Cinza-Sanjurjo reports receiving honoraria from Almirall, Bayer, Boehringer Ingelheim and Pfizer.