By Will Boggs MD
January 04, 2019
The risk of stroke should be reassessed annually in patients with atrial fibrillation (AF), because CHA2DS2-VASc scores used to determine the need for anticoagulation commonly rise over time, researchers from Taiwan report.
"The stroke risk of initially 'low-risk' AF patients is not static (and) is likely to increase during the follow-up after AF being diagnosed," Dr. Shih-Ann Chen from Taipei Veterans General Hospital and National Yang-Ming University, in Taipei, told Reuters Health by email. "In our report, around one-third of AF patients would acquire at least one new stroke risk factor after a mean follow-up of around 3 years."
International guidelines support withholding oral anticoagulants for low-risk patients with AF, i.e., those whose CHA2DS2-VASc scores are not greater than 0 (men) or 1 (women). Most patients with AF develop at least one new risk factor before presenting with ischemic stroke.
Dr. Chen and colleagues used data from the Taiwan National Health Insurance Research Database to investigate the incidence of an increase in CHA2DS2-VASc scores to at least 1 (men) or 2 (women) among patients with newly diagnosed AF whose baseline scores were 0 (men) or 1 (women).
During a mean follow-up of 3.24 years, 5,301 of 14,606 low-risk patients with AF (36.3%) acquired at least one new risk factor, the researchers report in Annals of Internal Medicine, online January 1.
The cumulative incidence of an increase of at least one point was 16.1% in men and 16.2% in women at one year, 24.5% and 24.9% at two years and 49.1% and 49.9% at seven years.
"Regular reassessment for stroke risk is necessary for AF patients, so that oral anticoagulants could be provided in a timely manner to avoid ischemic stroke when patients are not low-risk anymore," Dr. Chen said.
"Since about 16.1% of men and 16.2% of women who were initially at low risk would have a CHA2DS2-VASc score of at least 1 (men) or 2 (women) at 1 year after incident AF, the CHA2DS2-VASc scores should be reassessed at least annually in AF patients," he said.
"More clear recommendations for the importance of stroke risk reassessment, including the suggested timing interval, should be considered to be incorporated into the future guidelines to inform clinical practice," Dr. Chen added.
Dr. F. Russell Quinn of the University of Calgary, in Canada, who recently investigated factors influencing oral-anticoagulant prescription for AF patients presenting to emergency departments, told Reuters Health by email, "Since age is one of the risk markers, it is inevitable that the risk score will increase with time. So, it's not surprising that risk goes up with time, but it is striking that within 7 years, around half of the patients who are initially low risk will reach a risk score where anticoagulation should be considered."
"Because stroke can be such a devastating consequence of atrial fibrillation, physicians should have in place methods to periodically reassess the risk score of their patients," said Dr. Quinn, who was not involved in the study. "Physicians should look at their own follow-up practices to see how this can be achieved."
"With increasing use of electronic medical records, it should be feasible to have reminders programmed to flag important changes," Dr. Quinn said. "Patients can also be empowered to contribute to this process: with more and more use of smartphone apps to track personal health data, and with a little patient education, individuals could be prompted to review things with their physician if certain age boundaries or health milestones are reached. Since these patients can have contact with multiple health professionals (physicians, nurses, pharmacists, etc.), this could be an area where a 'shared care' model could work well."