Comparison of short-term outcomes of thrombolysis for in-hospital stroke and out-of-hospital stroke in United States

Abstract

Background and purpose: In-hospital stroke (IHS) differs from out-of-hospital stroke (OHS) in risk factors and outcomes. We compared IHS and OHS treated with thrombolysis from a large national cohort in a cross-sectional study to further clarify these differences.

Methods: The Nationwide Inpatient Sample for the years 2005-2010 was searched for adult acute ischemic stroke cases treated with intravenous or intra-arterial thrombolysis. Patients treated on the day of admission were classified as OHS. We compared the demographic and hospital characteristics, comorbidities, and short-term outcomes of thrombolysed IHS and OHS.

Results: IHS included 8.7% of 11 750 thrombolysed stroke cases in this study. IHS was associated with a higher comorbidity profile and higher rates of acute medical conditions compared with OHS. IHS had higher inpatient mortality (15.7% versus 9.6%; P<0.001) and lower rate of discharge to home/self-care (22.8% versus 30.0%; P<0.001). IHS was also associated with higher mortality among endovascular treatment group (19.3% versus 13.8%; P=0.010). The difference in the rate of all intracerebral hemorrhage was not significant (5.3% versus 4.7%; P=0.361). In the multivariate analysis, inpatient mortality (adjusted odds ratio, 1.59; 95% confidence interval, 1.32-1.92; P<0.001) and favorable discharge outcome (adjusted odds ratio, 0.79; 95% confidence interval, 0.67-0.93; P=0.005) remained significantly worse in IHS.

Conclusions: Thrombolysed IHS is associated with worse discharge outcomes compared with thrombolysed OHS, likely because of their higher comorbidities and additional medical reasons for the index admission. Thrombolysis is not associated with a higher rate of intracerebral hemorrhage among IHS.

Keywords: Nationwide Inpatient Sample; in-hospital stroke; intracerebral hemorrhage; ischemic stroke; thrombolysis.

Figure 1

Case-selection Flowchart. Endovascular treatment includes intra-arterial thrombolysis and/or mechanical embolectomy. IV indicates intravenous; MI, myocardial infarction; NIS, nationwide inpatient sample; PE, pulmonary embolism; tPA, tissue plasminogen activator.

Figure 2

Comparison of Outcomes between Thrombolysed In-Hospital Stroke and Out-of-Hospital Stroke. GI indicates gastrointestinal; ICH, intracerebral hemorrhage; IHS, in-hospital stroke; OHS, out-of-hospital stroke; and SNF, skilled nursing facility.