The impact of statin use prior to intensive care unit admission on critically ill patients with sepsis

Abstract

Objective: To evaluate the impact of pre-intensive care unit admission (pre-ICU) statin use on all-cause in-hospital mortality and ICU length of stay (LOS).

Design: Retrospective cohort study.

Setting: Adult ICUs at tertiary hospitals.

Patients: Adult critically ill patients diagnosed with sepsis admitted to the ICUs.

Intervention: The exposure was pre-ICU statin prescription (statin users); unexposed represented absence of pre-ICU prescription (non-users).

Measurement and main results: We used the 2001-2012 Medical Information Mart for Intensive Care-III (MIMIC-III) database to determine average treatment effect (ATE) of pre-ICU statin use on 30-day ICU mortality, ICU LOS, and 30-day in-hospital mortality using the Augmented Inverse Propensity Weighted technique (AIPW), after adjusting for confounding factors (age, race, health insurance, corticosteroids use, vital signs, laboratory tests, and Sequential Organ Failure Assessment score (SOFA). We measured 30-day ICU mortality as deaths within 30 days of admission to the ICU, and ICU LOS was measured in fractional days. A 30-day in-hospital mortality was measured as death within 30 days of hospital admission. A total of 8200 patients with sepsis were identified; 19.8% (1623) were statin users, and 80.2% (6577) were non-users. Most were Caucasian, aged 80 years and above, and male. After adjusting for confounding factors, pre-ICU statin use decreased 30-day ICU mortality (ATE, -0.026; 95% confidence interval [CI], -0.048 to -0.009); ICU LOS (ATE, -0.369; 95% Cl, -0.849 to -0.096); and 30-day in-hospital mortality (ATE, -0.039; 95% CI, -0.084 to -0.026) on average compared with non-statin use, respectively. In a stratified analysis, the result for ICU LOS (ATE, -0.526; 95% CI, -0.879 to -0.241) and 30-day in-hospital mortality (ATE, -0.023; 95% CI, -0.048 to -0.002) was consistent among patients admitted to the medical ICU.

Conclusions: Among patients with sepsis admitted to the medical ICU, pre-ICU statin use is causally associated with a decrease in 30-day ICU mortality, ICU LOS, and 30-day in-hospital mortality compared to non-use. This study adds to the totality of evidence on the pleiotropic effect of statin use in patients with sepsis.

Keywords: critical care; hydroxymethylglutaryl-CoA reductase inhibitors; length of stay; mortality; organ dysfunction scores; retrospective studies; septic shock.