Efficacy and safety of PCSK9 inhibitors for stroke prevention: Systematic review and meta-analysis

Abstract

Objective

Investigate the efficacy and safety of proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) on stroke prevention.

Background

PCSK9i reduce low-density lipoprotein cholesterol (LDL-C) and lipoprotein a (LpA) levels. Their efficacy in reducing the risk of major cardiovascular events has been shown in multiple randomized clinical trials (RCT). However, clinical equipoise remains on the magnitude and mechanisms by which PCSK9i decrease the risk of stroke.

Methods

We performed a systematic search of biomedical databases from inception to January 15, 2024, to identify RCTs that investigated the efficacy of PCSK9i versus placebo for major cardiovascular event prevention. The primary outcome was total stroke. The safety outcome was the risk of adverse neurological events, as defined by each trial. Effect size was represented by risk ratio (RR), and analysis was done using random-effects meta-analysis. Heterogeneity was assessed by I² and Cochrane Q statistics. Meta-regression analyses were performed to assess the association between LDL-C and LpA reduction and stroke risk.

Results

Overall, 20 studies with 93,093 patients were included. The quality of the evidence was moderate and heterogeneity for all comparisons was low (I² < 25 %). The mean age was 60.1 years for the PCSK9i group and 59.6 years for the placebo group, with a mean follow-up time of 60.1 weeks. PCSK9i reduced the LDL-C levels by 11 % and LpA levels by 8 %. PCSK9i were associated with a significant reduction in stroke risk (RR 0.75, 95 % CI 0.66-0.86, I² = 0 %), without an increase in mortality (RR 0.97, 95 % CI 0.87-1.08, I² = 0 %). The risk of adverse neurological events was similar between groups (RR 0.99, 95 % CI 0.84-1.18, I² = 11 %). In meta-regression analyses, the stroke risk was not associated with the magnitude of the effect of PCSK9i on LDL-C (LDL C β = -0.01, 95 % CI=-0.03-0.02) and LpA (β = -0.01, 95 % CI=-0.06-0.04) levels.

Conclusions

PCSK9i significantly reduced the stroke risk, without increasing mortality or the risk of adverse neurological events. Our findings also suggest that the beneficial effect of PCSK9i on stroke risk is mediated by LDL-C- and LpA-independent mechanisms.