What is the clinical evidence from this study?

Study design: Observational. Population: Syncope (n=570). Intervention: Diagnostic workup. Primary outcome: Proportion of patients with unknown/unexplained syncope after workup.

January 1, 2013Open Access

Unexplained Syncope and Diagnostic Yield of Tests in Syncope According to the ICD-10 Discharge Diagnosis

Key Result

Despite extensive diagnostic testing, the underlying etiology of syncope remained unexplained in 48% of patients after workup, highlighting the generally low diagnostic yield of routine tests.

Study Design

Type

Observational (n=570)

Multicenter

Yes

PICO

Population

Syncope (n=570)

Intervention / Comparator

Diagnostic workup

Primary Outcome

Proportion of patients with unknown/unexplained syncope after workup

Limitations

Retrospective study of hospitalized inpatient databases, missing outpatient or general practice cases
Gold standard relied solely on chart documentation without pre-specified criteria for correct diagnosis
Case definition of syncope only included 63% of all patients with syncope
Patients who received specific cardiac or orthostatic diagnoses at discharge were excluded by the R55.9 code
Could not account for factors that might have influenced the attending physician in ordering certain tests

Abstract

BACKGROUND: The etiology of syncope according to the discharge diagnosis from hospital admissions has not been examined before. Therefore the aims of this study were to examine the diagnostic yield of tests and frequency of unexplained cases during admission and after workup after an ICD-10 diagnosis of syncope. METHODS: A retrospective chart review of 600 patients discharged with the primary ICD-10 discharge diagnosis of syncope R55.9 was performed. Causes and clinical characteristics of syncope according to the physician were noted both after initial discharge and after workup. RESULTS: During a mean follow-up period of 2.5 years (SD: ± 1.30) several diagnostic tests were used (mean number of tests per patient was 4.7 (SD: ± -2.0)) and the mean length of admission was 2.1 days (± 1.5).The final diagnosis after workup was reflex syncope in 21%, cardiac 18%, orthostatic hypotension 10%, other causes 4% and unknown/unexplained syncope in 48% with wide age differences. The diagnostic yield of tests was generally low and differed widely depending on usage during admission or usage during subsequent workup. CONCLUSIONS: The underlying etiology of syncope remains difficult to establish despite the high use of diagnostic tests and the diagnostic yield of many tests implemented in the care path is generally low.

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