Wern Yew Ding, MBChB
Hypertension is well-recognized as a major risk factor for primary and recurrent strokes. Previous studies have shown that the use of blood pressure (BP)-lowering drugs among patients who have suffered an initial stroke is beneficial at reducing the risk of recurrent stroke, regardless of whether or not these patients had a documented history of hypertension. However, there is limited evidence focusing on patients with ischemic stroke (instead of all stroke types).
In this study by Boncoraglio and colleagues, the authors performed a systematic review and meta-analysis of 8 randomized controlled trials that included a total of 33774 patients with ischemic stroke or transient ischaemic attack who were randomized to receive either an anti-hypertensive agent vs. no treatment or placebo. The study was prospectively registered on PROSPERO, and a comprehensive search strategy was performed. Mean follow-up was 25 months. Overall, the authors reported that patients taking any BP-lowering drugs had a lower risk of subsequent stroke (OR 0.79 [95% CI, 0.66 – 0.94]), though there was no difference in mortality rates between the groups (OR 1.01 [95% CI, 0.92 – 1.10]). The lack of benefit in terms of mortality may be partly driven by the increased risk of serious adverse events including hypotension, syncope, falls, electrolyte abnormalities, bradycardia and acute kidney injury that was associated with treatment. The results suggest that anti-hypertensive agents were useful for the secondary prevention of stroke but were linked to a potential risk of serious side-effects.
The findings from this study further support the use of anti-hypertensive drugs in patients with ischemic stroke or transient ischemic attack. However, there are a few issues worth noting. Firstly, this meta-analysis comprised several historical studies, which may not reflect contemporary practice. Secondly, two of the included studies were designed to evaluate the use of anti-hypertensive drugs as an acute treatment following an ischemic stroke (randomization <48hrs), which may have introduced a confounding effect. Thirdly, there was significant heterogeneity (I2=61%) between the studies for the stroke outcome, suggesting that the results should be interpreted with caution. Finally, each of the studies evaluated a different anti-hypertensive drug, thereby precluding a direct comparison in order to determine the optimal drug regimen.
