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Abstract

Introduction: Many observational studies demonstrate a beneficial link between pre-existing statin therapy and the development of and outcomes from sepsis. These favorable effects have been ascribed to the pleiotropic effects of statins including their immune-modulatory, anti-inflammatory and anti-apoptotic properties. A recent randomized control trial however failed to show any benefit if statins were started after the onset of severe sepsis. It is therefore unclear whether improved outcomes are the result of protection conferred by statin therapy or the underlying condition necessitating their prescription. Methods: Using the Nationwide Inpatient Sample from 2005 to 2009, patients older than 18 years, discharged with severe sepsis were identified using ICD-9-CM codes. Hyperlipidemia was also identified using appropriate ICD-9CM codes. Outcome variables included in-hospital mortality, duration of mechanical ventilation and length of hospital stay. Chi square test and Wilcoxon rank tests were used to compare variables for unadjusted analysis. We performed nearest neighbor greedy matching to create cases and controls. We used multivariable regression to determine the independent association of hyperlipidemia with outcomes from severe sepsis. We adjusted for demographic and hospital characteristics, co-morbidities and severity of severe sepsis. Results: After matching, there were 70,840 patients in hyperlipidemia group and 59,801 in control group. The groups were matched in demographic and hospital characteristics, co-morbidities and severity of severe sepsis. The in hospital mortality in the hyperlipidemia group was significantly lower when compared to controls (19.7% vs. 24.2%, p<0.001). On logistic regression, the odd of mortality was 0.71 times lower in the hyperlipidemia group (95%Confidence Interval 0.68-0.75). The effect was more robust in younger population (age 18-35) whose odds ratio was even lower at 0.47 (95%CI 0.39-0.57). The median LOS, rates of invasive mechanical ventilation, prolonged mechanical ventilation and tracheostomy were significantly lower in the hyperlipidemia group. Conclusions: Hyperlipidemia is associated with lower mortality, shorter length of hospital stay and decreased use of mechanical ventilation in severe sepsis. This may be due to the use of statins in this group, however robust prospective trials are needed to confirm our hypothesis.