Statin and Its Association With Delirium in the Medical ICU*

Objectives: To examine the association between statin use and the risk of delirium in hospitalized patients with an admission to the medical ICU. Design: Retrospective propensity-matched cohort analysis with accrual from September 1, 2012, to September 30, 2015. Setting: Hartford Hospital, Hartford, CT. Patients: An initial population of patients with an admission to a medical ICU totaling 10,216 visits were screened for delirium by means of the Confusion Assessment Method. After exclusions, a population of 6,664 was used to match statin users and nonstatin users. The propensity-matched cohort resulted in a sample of 1,475 patients receiving statin matched 1:1 with control patients not using statin. Interventions: None. Measurements and Main Results: Delirium defined as a positive Confusion Assessment Method assessment was the primary end point. The prevalence of delirium was 22.3% in the unmatched cohort and 22.8% in the propensity-matched cohort. Statin use was associated with a significant decrease in the risk of delirium (odds ratio, 0.47; 95% CI, 0.38–0.56). Considering the type of statin used, atorvastatin (0.51; 0.41–0.64), pravastatin (0.40; 0.28–0.58), and simvastatin (0.33; 0.21–0.52) were all significantly associated with a reduced frequency of delirium. Conclusions: The use of statins was independently associated with a reduction in the risk of delirium in hospitalized patients. When considering types of statins used, this reduction was significant in patients using atorvastatin, pravastatin, and simvastatin. Randomized trials of various statin types in hospitalized patients prone to delirium should validate their use in protection from delirium.