APOE polymorphism is associated with risk of severe sepsis in surgical patients

Objective: To test for an association between apolipoprotein E (APOE) genotypes and the occurrence of severe sepsis in an elective surgical cohort. Design: Prospective, observational, single cohort study. Setting: Sixteen-bed surgical intensive care unit (ICU) at a university hospital. Patients: Patients were 343 patients with planned admission to the ICU after major elective noncardiac surgery. Interventions: Blood samples, together with demographic data, baseline clinical data, and Acute Physiology and Chronic Health Evaluation II scores, were collected on admission to the ICU and on each subsequent ICU day. APOE genotyping was conducted using a polymerase chain reaction-based assay. The primary outcome was diagnosis of severe sepsis; secondary outcomes included time on mechanical ventilation, ICU length of stay, and ICU mortality. Measurements and Main Results: Severe sepsis was diagnosed in 34 of 343 patients (9.9%). Carriers of the APOε3 allele (one or two copies) had a lower incidence of severe sepsis than patients with no APOε3 allele (p = .014), with a relative risk of 0.284 (95% confidence interval 0.127-0.635). The protective effect of APOε3 genotype on the incidence of severe sepsis remained significant (p < .01) after adjusting for age, gender, or race in a logistic regression model. Supporting our findings, presence of the APOε3 allele was also associated with fewer days spent in the ICU (p = .007). In contrast, APOE genotypes were not associated with duration of mechanical ventilation or ICU mortality. Conclusions: In an elective surgical cohort, presence of the APOε3 allele is associated with decreased incidence of severe sepsis and a shorter ICU length of stay.