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Syncope is common, challenging, and expensive; it accounts for 1% to 3% of all U.S. emergency department visits and about 6% of inpatient admissions, with an estimated annual healthcare cost of US$2.5 billion. Most causes of syncope are benign, but the diagnostic challenge is to identify those that are life-threatening, particularly cardiovascular causes. Despite thorough and costly work-ups, syncope etiology remains undetermined in ≥40% of patients after their initial evaluations.
Researchers at Yale University performed a retrospective cohort study in 2106 consecutive older patients (age, ≥65) who were admitted with syncope. The investigators reviewed how often various diagnostic tests were ordered and how often such results helped to establish the etiology of syncope or affected diagnosis and management. They calculated the cost per test that affected diagnosis or management and whether use of the San Francisco Syncope Rule (SFSR; Ann Emerg Med 2004; 43:224) resulted in improved cost efficiency or diagnostic yield.
Postural blood pressure measurement (i.e., orthostatics), performed in only 38% of cases, affected diagnosis and management in about 25% of patients and identified syncope etiology in 15% to 21% of syncopal episodes; it returned the highest diagnostic yield and was the most cost-effective test ($17–$21). Cardiac enzymes, head computed tomography (CT) scans, carotid ultrasound (US), and electroencephalography (EEG) had little effect on diagnosis or management (<5%); rarely helped determine syncope etiology (<2%); and were among the least cost-effective tests: EEG (≈$33,000), head CT (≈$25,000), cardiac enzymes (≈$22,000), and carotid US (≈$20,000). Use of the SFSR led to higher diagnostic yield and better cost-effectiveness for most cardiac tests.
Mendu ML et al. Yield of diagnostic tests in evaluating syncopal episodes in older patients. Arch Intern Med 2009 Jul 27; 169:1299.
Heidenreich PA. Assessing the value of a diagnostic test. Arch Intern Med 2009 Jul 27; 169:1262.
Comment
These findings underscore the importance of prioritizing diagnostic testing based on an initial standard evaluation, which should include a complete history and physical examination (including orthostatic blood pressure measurements and an electrocardiogram). Neurological tests (i.e., head magnetic resonance imaging or CT, EEG, and carotid US) shouldn't be performed, unless a neurological disease or event is suspected, based on the initial evaluation.
I am confident that the results of this study could be replicated in a variety of clinical settings. Although “shot gunning” multiple tests might reassure patients that they are getting the best care money can buy, we must take more financial stewardship of our resources, follow evidence-based guidelines, and be willing to live with some diagnostic uncertainty. Our healthcare system and economy can no longer support indiscriminate ordering of tests. More studies should be designed to evaluate cost-effectiveness, and those results should be incorporated into clinical guidelines.