New Tool Predicts Bleeding Risk After TIA, Ischemic Stroke

Megan Brooks

August 15, 2017

Researchers have developed and validated a new risk score called S2TOP-BLEED, which can predict 3-year risk for major bleeding in patients requiring antiplatelet therapy after transient ischemic attack (TIA) or ischemic stroke.

"This risk ranges from 2% for people aged 45 to 55 years with no additional risk factors, to over 10% for those 75 to 85 years old with multiple risk factors," Nina Hilkens, MD, University Medical Center Utrecht, the Netherlands, told Medscape Medical News.

"The S2TOP-BLEED score can be used in clinical practice to identify patients at high risk of bleeding after a TIA or ischemic stroke. In those patients at high risk, doctors may want to prescribe additional gastroprotective drugs and monitor blood pressure more closely."

"However," she added, "the S2TOP-BLEED score should not be used to guide treatment decisions for antiplatelet treatment, as bleeding risks have to be balanced against the risk of a recurrent stroke."

The study was published online August 2 in Neurology.

Development and Validation

To develop the S2TOP-BLEED score, the researchers merged patient data from six randomized clinical trials (CAPRIE, ESPS-2, MATCH, CHARISMA, ESPRIT, and PRoFESS) to obtain a derivation cohort of 43,112 patients.

Major bleeding occurred in 1530 of the 43,112 patients during 94,833 person-years of follow-up. The 3-year risk for major bleeding was 4.6% (95% confidence interval [CI], 4.4% to 4.9%).

The researchers quantified the association between clinical variables and major bleeding to obtain a logistic regression model that included 10 predictors: male sex, smoking, type of antiplatelet therapy (aspirin, clopidogrel), modified Rankin Scale score of 3 or greater, prior stroke, high blood pressure, lower body mass index, being elderly, Asian ethnicity, and diabetes.

The S2TOP-BLEED score had a c statistic of 0.63 (95% CI, 0.60 to 0.64) and showed "good calibration" in the development data, the researchers report. Major bleeding risk ranged from 2% in younger patients without additional risk factors to more than 10% in older patients with multiple risk factors.

"The increasing risk of bleeding with higher age seems particularly important," write Dr Hilkens and colleagues, "given the rising number of elderly patients with a TIA or ischemic stroke, with around 30% of strokes occurring in patients older than 80 years."

In an independent external validation cohort of 18,417 patients from the PERFORM trial, the model had a c statistic of 0.61 (95% CI, 0.59 to 0.63) and "slightly underestimated major bleeding risk," the researchers note.

They authors note that limitations of the study include that the score was based on people involved in clinical trials, who may not be representative of all people who have strokes. Also, only trials published by 2010 were included, and diagnosis and treatment of stroke have improved and changed since that time.

Refinement Needed

In an accompanying editorial, Robin Lemmens, MD, PhD, from University Hospitals Leuven, Belgium, and Rustam Al-Shahi Salman, PhD, from University of Edinburgh, United Kingdom, write that the researchers should be "congratulated for developing a well-executed and externally validated major bleeding risk score for patients with a probable non-cardio-embolic TIA or ischemic stroke treated with antiplatelet therapy, although the discrimination of the S2TOP-BLEED score currently limits its utility in clinical practice."

"Hilkens et al. combined data from 6 large randomized clinical trials, including patients from over the entire world to increase the generalizability of the risk score. The risk of major bleeding in the first year was similar to the 1.7% rate reported in a meta-analysis published in 2006, suggesting no drastic changes in the bleeding risk over the years," they add.

The S2TOP-BLEED score estimations may help in choosing between dual and single antiplatelet strategies.

"Data from the CHANCE trial suggest that the benefit of dual platelet might outweigh the risk of bleeding only in the first 2 weeks after the index TIA or stroke. Therefore, the S2TOP-BLEED score might guide physicians to shorten treatment duration for dual antiplatelet therapy in those patients with higher bleeding risk," the editorialists write.

"However, the accuracy of the S2TOP-BLEED score needs to improve before clinical implementation for individual patient decisions….  The score could be refined in future studies, potentially with a focus on predictors of intracranial bleeding, the most devastating complication of antithrombotic therapies," Dr Lemmens and Dr Salman conclude.

The study was supported by the Dutch Heart Foundation and the Netherlands Organization for Health Research and Development. Dr Hilkens, Dr Lemmens, and Dr Salman have disclosed no relevant financial relationships. A complete list of author disclosures is available with the original article.

Neurology. Published online August 2, 2017. Abstract, Editorial

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