1.29% of the patients without any CYP2C19 LoF genetic variants had an stroke during the prescribing period (mean 2.59 years between first and last clopidogrel prescription, SD 2.98) compared with 1.91% of the CYP2C19 LoF carriers: this absolute 0.64% excess is statistically significant (95% CI 0.021% to 1.35%, p=0.027). The gene discussed is CYP2C19; the disease is Stroke.