Can benign etiologies predict benign outcomes in high-risk syncope patients?

Background: We previously studied and validated risk factors for adverse outcomes or need for critical intervention in syncope.

Objective: To determine whether high-risk patients, diagnosed with benign etiologies of syncope after a normal emergency department (ED) work-up, sustain favorable outcomes.

Methods: Prospective, observational cohort of consecutive ED patients aged ≥ 18 years with syncope. Benign etiology was defined as vasovagal syncope or dehydration. Patients were followed up to 30 days to identify adverse outcomes including death, myocardial infarction, dysrhythmia, alterations in antidysrhythmics, percutaneous intervention, pulmonary embolus, stroke, metabolic catastrophe, or significant hemorrhage.

Results: Patients presented with benign etiologies in 164/293, 56% (95% confidence interval [CI] 50-62%) of cases. Of these, pathologic conditions were identified during ED evaluation in 11/164, 7% (95% CI 3-11%) of cases. This includes ED findings/treatments of blood transfusion, severe electrolyte disturbance, incarcerated hernia, rhabdomyolysis, subarachnoid hemorrhage, bowel obstruction, dysrhythmia, and transient ischemic attack. The remaining 153 with benign presentations had no adverse outcomes at 30 days, while 57/129 (44%) patients with non-benign etiologies had adverse outcomes in the hospital or within 30 days. Previously, we demonstrated a 48% reduction in admission rate if only patients with risk factors for adverse outcome were admitted. If patients with both benign etiologies and a negative ED work-up were sent home, even if they had risk factors for an adverse outcome, an additional 19% (95% CI 14-25%) reduction in hospital admissions would have occurred.

Conclusions: In patients with presentations consistent with a benign etiology of syncope (vasovagal or dehydration) where the ED work-up was normal, we found no patients who would benefit from hospitalization based on risk factors alone.