Key result
Extended-release dipyridamole plus aspirin failed to show noninferiority to aspirin alone for recurrent ischemic stroke (6.9% vs 5.0%; HR 1.47; 95% CI 0.93-2.31).
Why the study?
Does extended-release dipyridamole plus acetylsalicylic acid reduce recurrent ischemic stroke in Japanese stroke patients compared to 81 mg acetylsalicylic acid?
RCT (n=1,294)
Double-blind
randomized
Does extended-release dipyridamole plus acetylsalicylic acid reduce recurrent ischemic stroke in Japanese stroke patients compared to 81 mg acetylsalicylic acid?
Hazard Ratio: 1.47 (95% CI 0.93–2.31)
Absolute Event Rate: 6.9% vs 5%
In Japanese stroke patients, extended-release dipyridamole plus aspirin failed to show noninferiority to aspirin alone for preventing recurrent ischemic stroke, though the study was limited by low event rates and short follow-up.
Not noninferior for recurrent stroke prevention in Japanese patients; challenges combination therapy and supports aspirin monotherapy.
BACKGROUND: Despite improvements in treatment, stroke still carries a high death toll and disability in Asia. Extended-release dipyridamole (ER-DP) plus acetylsalicylic acid (ASA) has consistently been shown to be superior over conventional platelet inhibition by ASA. ER-DP plus ASA is well established in the secondary prevention of stroke in a lot of countries including the USA and Europe. DP has an established benefit in the treatment of heart disease in Japan; however, for the prevention of stroke, the fixed-dose combination of ER-DP plus ASA has only been investigated in a small number of patients in Japan. METHODS: The aim of this double-blind, randomized clinical trial was to investigate the efficacy and safety of ER-DP plus ASA versus 81 mg ASA over 1 year. The primary end point of this study was the event rate of recurrent ischemic stroke (fatal or nonfatal) using the Kaplan-Meier method and Cox regression analysis. RESULTS: Of the 1,294 enrolled patients, the primary end point was analyzed in 652 patients in the ER-DP plus ASA group and 639 in the ASA group. The incidence of ischemic stroke was 6.9% for ER-DP plus ASA and 5.0% for ASA with a hazard ratio of 1.47 (95% confidence interval 0.93-2.31) for the primary end point. The ASA treatment group was found to have a lower than expected yearly event rate, compared to other studies in Japanese stroke patients. Noninferiority of ER-DP plus ASA versus ASA could not be shown. The risks of major bleeding events and intracranial hemorrhage were found to be similar between the treatment arms. There were 4 deaths (0.6%) in the ER-DP plus ASA group and 10 (1.6%) in the ASA group. CONCLUSIONS: The results of the study are inconclusive. Noninferiority of ER-DP plus ASA versus ASA could not be established, a difference between treatments could not be shown for the primary end point. Possible reasons for this result include a small sample size, low event rates and too short a treatment duration (ClinicalTrials. gov number, NCT00311402).
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Uchiyama et al. (2011) conducted an RCT in stroke (n=1,294). Extended-release dipyridamole plus aspirin vs. 81 mg aspirin was evaluated on recurrent ischemic stroke (fatal or nonfatal) (HR 1.47, 95% CI 0.93-2.31). Extended-release dipyridamole plus aspirin failed to show noninferiority to aspirin alone for recurrent ischemic stroke (6.9% vs 5.0%; HR 1.47; 95% CI 0.93-2.31).
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