Study reveals 'substantial incidence' of atrial fibrillation in primary care patients

Researchers reported finding higher rates of atrial fibrillation among a large primary care population compared with previous estimates in community-based research cohorts.

Shaan Khurshid, MD, MPH, a cardiology clinical and research fellow at Massachusetts General Hospital, and colleagues wrote in JAMA Network Open that ascertaining the frequency of atrial fibrillation (AF) — “a common and morbid arrhythmia” — is challenging because of inaccurate diagnostic codes and the fact that AF may be paroxysmal.

“Rigorous contemporary estimates of AF prevalence and incidence are needed to inform interventions to reduce the public health burden of AF,” the researchers wrote.

Khurshid and colleagues conducted a secondary analysis of the VITAL-AF trial to quantify the incidence and prevalence of clinically diagnosed AF among primary care patients at a large academic medical center. They analyzed electronic health record data from 17,238 patients — 56% of whom were women and 83.4% of whom were white — who were enrolled from July 31, 2018, to Oct. 8, 2019.

The researchers assessed the prevalence rate at study entry and incidence rates per 1,000 person-years (PY) over a 1-year follow up. The analysis was stratified by comorbidities and demographic characteristics. They noted that race was self-reported and “included as a stratification variable given prior associations with diagnosed AF.”

Of the 17,238 participants, Khurshid and colleagues found that 13.2% had prevalent AF. Of the nearly 15,000 who did not have prevalent AF, the incidence rate was 23.7 per 1,000 PY (95% CI, 21-26.7). Both AF incidence and prevalence increased with age, the researchers wrote. Prevalence increased from 6.4% for those aged 65 to 69 years to 28.5% for those aged 85 years, and incidence increased from 14.2 per 1,000 PY for those aged 65 to 69 years to 50.8 per 1,000 PY for those aged 85 years.

“New AF incidence was substantial, and nearly one-third of individuals 85 years or older had prevalent AF,” Khurshid and colleagues wrote.

Additionally, the researchers found that AF incidence was greater in men compared with women — 33.4 per 1,000 PY vs. 16.8 per 1,000 PY, respectively.

They also wrote that their findings may be limited in that the sample “may possess characteristics affecting generalizability, although more than 70% of U.S. individuals 65 years or older receive primary care.”

“Overall, our findings suggest higher AF rates in primary care populations vs community-based research cohorts,” Khurshid and colleagues concluded. “This cohort study’s findings may prove useful to studies and programs focusing on AF prevention, diagnosis, and management.”