Comparative effectiveness of amlodipine versus nifedipine prescribed at discharge in patients with ischemic stroke or transient ischemic attack: A nationwide 5-year follow-up registry study

BACKGROUND: Amlodipine and nifedipine are the most commonly prescribed calcium channel blockers (CCB) for patients suffering from ischemic stroke or transient ischemic attack (TIA). Nevertheless, there is a scarcity of direct comparative evidence on their effectiveness. This study aimed to compare the effectiveness of amlodipine and nifedipine in patients with ischemic stroke or TIA. METHODS AND FINDINGS: This observational study was based on the Third China National Stroke Registry, which recruited consecutive adult patients with ischemic stroke or TIA from 2015 to 2018. In this study, ischemic stroke or TIA patients were prescribed either amlodipine or nifedipine at discharge. The primary outcome was the distribution of modified Rankin Scale (mRS) score, which assesses functional outcomes in patients with stroke, at 5 years. The intergroup differences were examined using ordinal logistic regression, yielding odds ratios (OR) and 95% confidence intervals (CI). Patient age, gender, body mass index, systolic blood pressure at admission, and onset date were adjusted. To improve baseline characteristic balance, inverse probability of treatment weighting (IPTW) was implemented. A total of 2,859 eligible patients were included, and there were 1847 patients in the amlodipine group and 1,058 patients in the nifedipine group after IPTW. The amlodipine group demonstrated significantly lower 5-year mRS scores in comparison to the nifedipine group, with an OR of 0.76 (95% CI [0.65, 0.89]; p < 0.001). A total of 956 (51.76%) amlodipine users and 632 (59.74%) nifedipine users achieved a mRS score > 0 at 5 years, with an OR of 0.71 (95% CI [0.61, 0.83]; p < 0.001). The sensitivity analyses yielded consistent results. The main limitations include the inherent observational design, the exclusive reliance on registry data, and relatively high loss-to-follow-up rate at 5 years. CONCLUSIONS: This study revealed that amlodipine, compared to nifedipine, may be associated with improved functional recovery in ischemic stroke or TIA patients. Randomized controlled trials are warranted to confirm these findings and refine CCB therapy.