Point-of-care screening did not affect diagnosis of afib in primary care, study finds

In a randomized trial at 16 primary care clinics in Massachusetts, rates of new afib diagnosis at one year were 1.72% with afib screening of older patients using a single-lead electrocardiogram versus 1.59% with usual care.

Using a handheld single-lead electrocardiogram (ECG) to screen for atrial fibrillation at primary care visits did not increase diagnosis rates compared with usual care, a recent industry-funded study found.

Between July 31, 2018, and Oct. 8, 2019, researchers randomized 16 primary care clinics in the Massachusetts General Hospital Primary Care Practice Based Research Network to perform atrial fibrillation screening with a handheld single-lead ECG during vital sign assessments or to provide usual care in patients ages 65 years of age or older. Patients' primary care clinicians received the screening results and made all decisions about confirmatory diagnostic tests and treatments. The primary outcome was incidence of newly diagnosed afib during the 12-month screening period, and secondary outcomes included change in incidence proportion of afib from the 12-month window before the screening period, a new diagnosis of afib associated with a primary care clinic visit, and a new entry for an oral anticoagulant on the medication list in the 12 months after initial enrollment. The results of the study, which was funded by the Bristol Myers Squibb-Pfizer Alliance, were published March 2 by Circulation.

The study included 30,715 patients without prevalent afib, 15,393 assigned to screening and 15,322 assigned to control. Median follow-up was 279 and 282 days, respectively. Mean age in each group was approximately 74 years, and over 84% of patients in each group were White. Of the screening group, 91% were screened, and 1.72% had new afib diagnosed at one year versus 1.59% in the control group (risk difference, 0.13% [95% CI, −0.16% to 0.42%]; P=0.38). Patients ages 85 years and older had higher rates of new afib diagnoses in both the screening and control groups (5.56% vs. 3.76%, respectively; risk difference, 1.80% [95% CI, 0.18% to 3.30%]). Only a small difference was seen in new afib diagnoses between the screening period and the previous year (0.32% in the screening group vs. −0.12% in the control group; risk difference, 0.43% [95% CI, −0.01% to 0.84%]). The screening and control groups did not differ in the proportion of patients with new afib diagnoses who began taking oral anticoagulants (73.5% vs.70.8%, respectively; risk difference, 2.7% [95% CI, −5.5% to 10.4%]).

The authors concluded that screening for afib with a single-lead ECG at primary care visits did not affect new afib diagnoses in adults ages 65 years and older and that their results probably reflect a low prevalence of undiagnosed afib in patients ages 65 to 84 years. “In contrast to some existing guidelines, our findings raise uncertainty about the use of single lead ECGs to opportunistically screen individuals aged at least 65 years of age for AF [atrial fibrillation] in primary care settings,” they wrote. “Our results suggest that point-of-care screening for AF may be clinically effective among those with advanced age but this secondary result warrants further evaluation.”