Statin therapy on admission to intensive care and outcome: an observational cohort study

Introduction

Statins are powerful hypolipaemic drugs that are proven to improve survival in patients with atherosclerosis. Their effects are not limited to lowering cholesterol but also include anti-inflammatory and antioxidative properties. For these reasons, it has been postulated that statins may reduce mortality in critically ill patients. We aimed to investigate the association between statin therapy on admission and outcome from intensive care in our ICU.

Methods

A prospective case-note review of 504 consecutive admissions to Glasgow Royal Infirmary ICU was undertaken over an 18-month period. Details of statin prescription, cardiovascular co-morbidity and smoking status was sought from the patients' case notes by hand using details of current and previous admissions, clinical letters, results of investigations and correspondence from the patient's general practitioner, using agreed criteria. Demographic, Acute Physiology and Chronic Health Evaluation II (APACHE II) score and outcome data were retrieved from the Ward Watcher system in the ICU.

Results

Complete data were available for 444 patients. One hundred and eleven (25%) of these were on statin therapy on admission to intensive care. All data are expressed as mean ± 95% confidence interval or median (interquartile range). Differences between groups were tested using the chi-squared test, Mann-Whitney test and unpaired Student's t test. Compared with patients without concurrent statin therapy, patients on statin therapy are more likely to be male (76.6% vs 63%, P = 0.009), older (65.2 ± 1.93 years vs 49.7 ± 1.86 years, P < 0.001), have a higher APACHE II score (20 (15 to 25) vs 16 (11 to 23), P < 0.001), have ischaemic heart disease (69.4% vs 17.1%, P < 0.001), and have hypertension (47.5% vs 0.22%, P < 0.001). There was no significant difference in mortality in the ICU (27.9% vs 27%, P = 0.86) or the hospital (40.5% vs 31.2%, P = 0.07).

Conclusions

Statin therapy does not significantly alter ICU or hospital mortality in our population. There are significant differences in APACHE II scores between the groups and predicted mortality which may suggest that patients on statins fare better than predicted, based upon their co-morbidities.