Is statin therapy after ischaemic stroke associated with increased intracerebral hemorrhage? The association may be dependent on intensity of statin therapy.

Background: There has been concern that statin therapy may be associated with an increased risk of intracerebral hemorrhage (ICH). We investigated whether the intensity and type of statin therapy instituted after ischemic stroke (IS) were associated with risk of future ICH in a region of northern China with a high incidence of stroke.

Methods: Newly diagnosed IS patients who were not treated with lipid-lowering drugs in the Beijing Employee Medical Claims Data database from 2010 to 2017 were included. The primary exposure variable was any statin prescription within 1 month of the first documented stroke diagnosis. High-intensity statin therapy was defined as atorvastatin ⩾ 80 mg, simvastatin ⩾ 80 mg, pravastatin ⩾ 40 mg, and rosuvastatin ⩾ 20 mg per day or equivalent combination. An adjusted Cox proportional hazards model was used to estimate the hazard ratio (HR) for ICH during follow-up in groups exposed and not exposed to statins.

Results: Of 62,252 participants with IS and 628 ICH readmissions were recorded during a median follow-up of 3.17 years. The risk of ICH among statin users (N = 43,434) was similar to that among nonusers (N = 18,818) with an adjusted HR and 95% confidence interval (CI) of 0.86 (0.73, 1.02). Compared with non-statin therapy, patients with low/moderate-intensity therapy had a lower risk of ICH (0.62: 0.52, 0.75), while patients with high-intensity therapy had a substantially higher risk (2.12: 1.72, 2.62). For patients with different types of statin therapy, adherence to rosuvastatin had the lowest risk of ICH compared to adherence to atorvastatin (0.46: 0.34, 0.63), followed by simvastatin (0.60: 0.45, 0.81).

Conclusion: In patients with IS, any statin therapy was not associated with an increased risk of ICH. However there appeared to be differential risk according to the dose of statin with high-intensity statin therapy being associated with an increased risk of ICH, while low/moderate-intensity therapy was associated with a lower risk.