Testing the dependency of the variables used for stratification using Chi-squared test, we obtained that being older or younger than 70 years is related with sex (p < 0.0001), HBP (high blood pressure) (p < 0.0001), SaO2 < 90% (p < 0.0001), LDH < 677 U/L (p = 0.0004) and CRP < 131 mg/L (p = 0.0023). This evidence concerns the gene CRP and hypertensive disorder.