Risk of stroke following SARS-CoV-2 infection in a nationwide self-controlled case series study in qatar

This study investigated stroke incidence after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection using Qatar’s nationwide stroke registry linked with national testing, vaccination, and mortality databases. A self-controlled case series design was implemented among individuals with stroke and confirmed primary SARS-CoV-2 infection between January 1, 2020, and April 11, 2023. Incidence rate ratios (IRRs) comparing stroke incidence rate during the 1–90 days post-infection with predefined control periods were estimated using conditional Poisson regression. Of 4,187 stroke cases, 338 with confirmed infection met inclusion criteria. Stroke incidence rate was elevated during the 1–90 days post-infection (IRR 1.84, 95% CI: 1.31–2.58), peaking at days 1–28 (IRR 2.22, 95% CI: 1.53–3.22) and declining thereafter (days 29–59: IRR 1.47, 95% CI: 0.97–2.24; days 60–90: IRR 0.72, 95% CI: 0.43–1.21). This corresponded to 5.9 excess strokes per 100,000 infections. Elevated risk was confined to pre-Omicron infections (IRR 2.98, 95% CI: 1.89–4.70), with no evidence of increased risk observed for Omicron infections (IRR 0.82, 95% CI: 0.46–1.45). Subtype analyses showed increased risk for ischemic stroke (IRR 1.99, 95% CI: 1.37–2.89) and cerebral venous sinus thrombosis (CVST; IRR 3.52, 95% CI: 1.15–10.78), but not hemorrhagic stroke (IRR 0.64, 95% CI: 0.16–2.51). SARS-CoV-2 infection was associated with a transient elevation in stroke risk, peaking shortly after infection and declining thereafter. Excess risk was confined to pre-Omicron infections and driven primarily by ischemic stroke, while CVST, though rare, showed the strongest relative effect.