Opportunistic Screening Best Option for Detection of Atrial Fibrillation

August 16, 2007 — New research suggests that opportunistic screening is more effective than usual care in detecting atrial fibrillation (AF) and is less costly than systematic screening in patients aged 65 years and older.
In the first large-scale study to evaluate detection methods of AF, investigators at the University of Birmingham, United Kingdom, found virtually identical rates of detection between opportunistic and systematic AF screening but found a major difference in rates of detection between AF screening of either type and usual care.
These results, the study's lead author David Fitzmaurice, MBChB, MRCGP, MD, FRCGP, told Medscape, warrant a sea change in how primary care clinicians approach older patients.
"If we're serious about identifying these patients, then we have to introduce a screening program. The clinical difficulty with atrial fibrillation is the majority of patients are asymptomatic, so you have to actively screen for it, seek it out," he said.
The study is published online in the August 2 issue of the BMJ.
Haphazard Approach
Currently, added Dr. Fitzmaurice, the approach to detection of AF is "fairly haphazard." In general, he said patients with AF are picked up once they are symptomatic or are fortuitously identified when they go to the clinician for an unrelated complaint, and, in the course of the office visit, they have their pulse or blood pressure taken.
"We know that with oral anticoagulation therapy, we can reduce stroke risk [in patients with AF] by two thirds, which is a phenomenal effect. But the key to stroke prevention lies in identifying these high-risk individuals," he said.
AF is a major risk factor for thromboembolic disease; the study suggests that prevalence of AF occurs in up to 7% of individuals older than 65 years.
This multicentered, cluster, randomized controlled trial I of computerized general practices in England included 14,802 patients aged 65 years or older from 50 practices in England. Half the practices were slated as intervention ones and were randomly allocated to either systematic screening or opportunistic case finding. The primary endpoint was new cases of AF during the 12-month study period.
Systematic screening involved inviting the entire target population — those older than 65 years — to undergo electrocardiography. The opportunistic case finding approach meant that target subjects routinely had their pulse taken and, if it was abnormal, underwent an electrocardiogram.
The remaining 25 practices, which served as controls, continued to provide usual care to their older patients and screened for and diagnosed AF as they normally would. The study's primary endpoint was newly identified AF.
Virtually Identical Rates of Detection
Investigators found the rates of detection of new cases of AF as 1.63% per year in the intervention practices vs 1.04% in the control practices. However, systematic screening and opportunistic case finding detected similar numbers of new cases: 1.62% vs 1.64%, respectively.
In light of the fact that rates of detection were essentially identical for the 2 screening methods of AF, Professor Fitzmaurice said that the more invasive approach and significant costs associated with systematic screening, which are about 5-fold greater than the opportunistic case-finding approach, cannot be justified.
"I think it is fairly clear now that we need to introduce a [AF] screening program. As long as you have an organized primary care system with good coverage of your patient population and physicians routinely take the pulse of all patients over age 65, opportunistic screening is the best and most cost-effective method of detecting atrial fibrillation," he said.
"Over and above that, it is clear that [AF] screening will pick up more patients than routine care," he added.
The NHS research and development health technology assessment programme funded the study. The authors have disclosed no relevant financial relationships..
BMJ. Published online August 2, 2007.