The highest quartile (compared with the lowest quartile) of serum HO‐1 was significantly, independently associated with a lower risk of poor functional outcome (adjusted OR 0.13, 95% CI 0.04–0.45; p = 0.001; ptrend < 0.001), after adjusting for age, sex, NIHSS, AF, alcohol consumption, current smoking, TOAST, and reperfusion therapy (Table 2, Figure S1 and Table S3). The gene discussed is HMOX1; the disease is atrial fibrillation.