Abstract 3889: Diagnosis of Transient Ischemic Attack Varies by Neurologist

Abstract

Introduction: The short duration of symptoms and multitude of non-vascular mimics make diagnosis of transient ischemic attack (TIA) subjective and challenging. Physician practice may influence whether a patient receives the diagnosis of TIA. Pathophysiology is the same for TIA and ischemic stroke (IS). Therefore, the proportion of TIA versus IS diagnoses should be the same across demographic and clinical strata and theoretically should not vary between physicians. Hypothesis: The TIA-IS ratio, defined as the proportion of TIA among all TIA and IS cases, varies between medicine and neurology services and between board-certified vascular and other neurologists. Methods: TIA and IS cases were identified using primary ICD9 discharge codes at Montefiore Medical Center from January 2009 through June 2011. Each TIA diagnosis was confirmed by chart review, excluding cases with acute IS on brain imaging, duration >24 hours or a clearly non-vascular syndrome. The TIA-IS ratio was assessed based on the primary ICD9 code and again on the diagnosis by chart review for discharges from the neurology versus the medicine service and also individually for each board-certified neurologist with more than 25 IS or TIA discharges during the study period. Mantel-Hantsel chi-square was used for univariate statistical comparison between groups. Results: There were 659 cases of TIA and 1927 cases of IS by primary ICD9 discharge code, for an overall TIA-IS ratio of 25.5 %. The ratio was higher for discharges from medicine (28.6%) than neurology services (23.8%, p=0.009). The ratio was higher for 12 non-vascular neurologists (27.0%, range 17.9-44.4%, 904 cases), than 5 vascular neurologists (20.0%, range 18.7-23.0, 715 cases, p=0.001). Chart review reduced the overall TIA-IS ratio to 16.3% and the difference between medicine and neurology discharges became non-significant but non-vascular neurologists still had a higher TIA-IS ratio (20.7%) than vascular neurologists (14.4%, p=0.001). Conclusions: The TIA-IS ratio is different on medicine and neurology services and varies widely among board-certified neurologists, with vascular neurologists less likely to assign the diagnosis of TIA than other neurologists even after excluding obvious non-TIA cases. The ABCD2 score, assessing patients’ symptoms and vascular risk factors, is promoted as a criterion for admission; however, these data suggest that physician training and perspective affect the diagnosis, and thus assessment of future stroke risk, as well.