The retrospective study found that the delirium rate in patients on statins, including atorvastatin, pravastatin, and simvastatin, was about half (or even less) than that of patients not on statins.

ICU patients who took statins had lower risk of delirium than those not on the drugs, according to a recent retrospective study.

The retrospective cohort analysis included patients from a single hospital's medical ICU, treated between Sept. 1, 2012, and Sept. 30, 2015. A total of 10,216 patients were screened for delirium with the Confusion Assessment Method (CAM). After exclusions, a sample of 1,475 statin users was propensity matched 1:1 with control patients not using statins. Results were published by Critical Care Medicine on June 15.

Based on the CAM, 22.3% of the patient population prior to matching developed delirium during their ICU stay, as did 22.8% in the propensity-matched cohort. Statin use was associated with a significant decrease in the risk of delirium (odds ratio [OR], 0.47; 95% CI, 0.38 to 0.56). Specific statins were also significantly associated with reduced frequency of delirium, including atorvastatin (OR, 0.51; 95% CI, 0.41 to 0.64), pravastatin (OR, 0.40; 95% CI, 0.28 to 0.58), and simvastatin (OR, 0.33; 95% CI, 0.21 to 0.52).

Previous research on the effect of statins on delirium prevention has had mixed results, the study authors noted. It is biologically plausible that the medications could have such effects, given their pleiotropic properties. In particular, lipophilic statins, such as simvastatin and atorvastatin, “are thought to be more likely to cross the blood-brain barrier via passive diffusion, and in theory, … may be more effective in treating or preventing cognitive dysfunction,” the authors said. However, this study also found a reduction in delirium with pravastatin and may have been underpowered to find an effect from rosuvastatin, both hydrophilic statins.

The study's limitations included that it had no data on any temporal associations between medication administration and the occurrence of delirium and that it faced the risk of confounding and bias inherent in a retrospective study, despite efforts at adjustment. Prospective randomized trials of various statins in hospitalized patients prone to delirium should be conducted to validate these results, the authors said.

REF: Delirium