Increased Risk for Ischemic Stroke in First 6 Months After Intracerebral Hemorrhage Diagnosis

There may be an increased risk for ischemic stroke in elderly patients with intracerebral hemorrhage (ICH) in the first 6 months after diagnosis, according to a study published in Stroke.

In this retrospective cohort study, researchers used both inpatient and outpatient claims data on a 5% sample of Medicare beneficiaries collected between January 2008 and December 2014 (n=1,760,439). The exposure variable was ICH, identified by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 431.x. The primary outcome was a composite of acute ischemic stroke and myocardial infarction (MI); secondary outcomes were ischemic stroke alone and MI alone.

Of the selected Medicare beneficiaries, 0.3% were diagnosed with ICH (n=5924). Arterial ischemic events were diagnosed in 7.8% of the cohort (n=137,912). The risk for an arterial ischemic event was found to be increased in the 6-month period following an ICH, with peaks in the first month (hazard ratio [HR], 6.7; 95% CI, 5.0-8.6) and the second month (HR, 4.6; 95% CI, 3.0-6.2) after ICH diagnosis. The slope of event-free survival was significantly lower for patients with vs without ICH, and the cumulative incidence of an arterial ischemic event was 5.7% in patients with ICH (95% CI, 4.8%-6.8%) and 1.8% in patients without ICH (95% CI, 1.7%-1.9%).

Limitations of this study included the lack of information on antithrombotic medication use and interruption. To palliate this gap, investigators performed a sensitivity analysis in which patients with atrial fibrillation or valvular heart disease were excluded. In addition, some participants may have been misclassified due to the use of ICD-9-CM codes, and the claims-based nature of the Medicare dataset did not allow researchers to investigate the etiology of ischemic strokes. “Further study of the link between ICH and subsequent ischemic stroke may yield new strategies for improving long term recovery after ICH,” noted the study authors. 

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Murthy SB, Diaz I, Wu X, et al. Risk of arterial ischemic events after intracerebral hemorrhage [published online November 27, 2019]. Stroke. doi: 10.1161/STROKEAHA.119.026207