Risk of Ischemic Stroke after an Inpatient Hospitalization for Transient Ischemic Attack in the United States

<b><i>Introduction:</i></b> A diagnosis of transient ischemic attack (TIA) must be followed by prompt investigation and rapid initiation of measures to prevent stroke. Prior studies evaluating the risk of stroke after TIA were conducted in the emergency room or clinic settings. Experience of patients admitted to the hospital after a TIA is not well known. We sought to assess the early risk of ischemic stroke after inpatient hospitalization for TIA. <b><i>Methods:</i></b> We used the 2010–2015 Nationwide Readmissions Database to identify all hospitalizations with the primary discharge diagnosis of TIA and investigated the incidence of ischemic stroke readmissions within 90 days of discharge from the index hospitalization. <b><i>Results:</i></b> Of 639,569 index TIA admissions discharged alive (mean ± SD age 70.4 ± 14.4 years, 58.7% female), 9,131 (1.4%) were readmitted due to ischemic stroke within 90 days. Male sex, head/neck vessel atherosclerosis, hypertension, diabetes, atrial flutter/fibrillation, previous history of TIA/stroke, illicit drug use, and higher Charlson Comorbidity Index score were independently associated with readmissions due to ischemic stroke. Ischemic stroke readmissions were associated with excess mortality, discharge disposition other than to home, and elevated cost. <b><i>Conclusions:</i></b> Patients hospitalized for TIA have a lower risk of ischemic stroke compared to that reported in the studies based on the emergency room and/or outpatient clinic evaluation. Among these patients, those with cardiovascular comorbidities remain at a higher risk of readmission due to ischemic stroke despite undergoing an inpatient evaluation and should therefore be the target for future preventive strategies.