Logistic regression adjusting for ethnicity, gender, age, APACHE II, site of infection, chronic heart failure, COPD, chronic steroid treatment, chronic dialysis and chronic hepatic failure, lactate concentration, norepinephrine dose and IL-6 concentrations showed that plasma HBP concentrations remained associated with presence of severe hypoxemia as defined above (P = 0.003). This evidence concerns the gene IL6 and chronic obstructive pulmonary disease.