Statin therapy prior to ICU admission: protection against infection or a severity marker?

Objective: Examine the impact of previous statin therapy on hospital mortality and whether it is due to a protective effect against ICU-acquired infections. Design and setting: Cohort comparison study by retrospective chart-based analysis in a 26-bed, university-affiliated, medical-surgical ICU. Patients: We analyzed data from 438 patients at high risk of ICU-acquired infections, i.e., those receiving mechanical ventilation for more than 96 h, 38 (8.7%) of whom had been treated with statins prior to and during ICU admission. Measurements and results: We recorded clinical characteristics, number and type of ICU-acquired infections, and ICU and hospital mortality. Statin-treated patients were older (71.7 +/- 8.3 vs. 61.5 +/- 18.3 years), but differences in predicted mortality risk by APACHE II (39.5 +/- 24.7 vs. 35.8 +/- 24.3%) did not reach statistical significance. The ICU-acquired infection rate in statin-treated patients was nonsignificantly lower (29% vs. 38%) and delayed (median 12 vs. 10 days), without differences regarding the source of infections. Nevertheless, hospital mortality was significantly higher in statin-treated patients (61% vs. 42%), even after adjustment for APACHE II predicted risk (observed/expected ratio 1.53 vs. 1.17). Conclusions: Statin therapy is associated with worse outcome, probably because underlying clinical conditions are insufficiently considered in mortality predictors. Its presumed protective effect against ICU infections remains unconfirmed.