Medical Excellence - Issue 2

unexpectedly low in such a high-risk cohort. In particular, low- grade stenoses (<50% or <70%) were relatively rare. Possibly minor vessel changes were under-reported, as the ultrasound examiner may have focused on ‘relevant’ high-grade findings. However, as our analysis focused on high-grade stenoses (≥50% or ≥70%), it is unlikely that this caused relevant bias. Importantly, the nature of our analyses was explorative, as many determinants were tested for multiple dependent variables. Despite provisions to reduce the number of statistical tests (see Methods section), 15 determinants were tested for six dependent variables, resulting in 90 primary tests. A Bonferroni correction would have reduced the p value to 0.0005, which is an unlikely p value in multivariate models in a cohort of this size. Therefore, all results have to be interpreted with caution. Conclusions We here reported for the first time follow-up stroke rates in pa- tients with isolated transient vertigo. Identifying patients with cerebrovascular vertigo remains difficult. Presentation mode (patients who presented because of vertigo) was found to be the only consistent risk factor for cerebrovascular vertigo and future risk for stroke or TIA. However, the clinical benefit of this finding may be limited. Confirmation in an independent pro- spective sample is needed. Abbreviations BPPV: Benign paroxysmal positional vertigo; CI: Confidence interval; CT: Computed tomography; DSA: Digital subtraction angiography; DWI: Diffusion-weighted imaging; LDLc: Low-density lipoprotein cholesterol; MRI: Magnetic resonance imaging; TIA: Transient ischemic attack; VRFs: Vascular risk factors Acknowledgments Not applicable. Funding No funding. Availability of data and materials The datasets used and analyzed in the current study are available from the corresponding author on reasonable request. Authors ’ contributions CH participated in the design of the study and collected and reviewed data. LW collected data and performed statistical analysis. TB collected data, per- formed statistical analysis, interpreted data and drafted the manuscript. ML designed the study, performed statistical analysis, interpreted data, drafted and critically revised the manuscript. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Consent for publication Not applicable. Ethics approval and consent to participate The study was conducted according to the principles of the Declaration of Helsinki, and approved by the ethics committee of the Faculty of Medicine, Goethe-University Frankfurt (Application No. 237/14). Publisher ’ s Note Springer Nature remains neutral with regard to jurisdictional claims in pub- lished maps and institutional affiliations. References 1. Burt CW, Schappert SM. Ambulatory care visits to physician offices, hospital outpatient departments, and emergency departments: United states, 1999–2000. 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