The Relationship Between Delirium and Statin Use According To Disease Severity in Patients in the Intensive Care Unit

Abstract

Background There have been few earlier studies on the efficacy of statins in the prevention of delirium. However, the results were controversial. The aim of this study was to investigate the association between the use of statins and the occurrence of delirium in a large cohort of patients in the intensive care unit (ICU), considering disease severity and statin properties, which were not sufficiently considered in the previous works. Methods We obtained clinical and demographical information from 3604 patients admitted to the ICU of Gangnam Severance Hospital from January 2013 to April 2020. This included information on daily statin use and delirium state, as assessed by the Confusion Assessment Method for ICU. We used inverse probability of treatment weighting and categorized the ICU patients into four groups based on the Acute Physiology and Chronic Health Evaluation II score (group 1: 0-10 - mild; group 2: 11-20 – mild to moderate; group 3: 21-30 – moderate to severe; group 4: > 30 - severe). We analyzed the association between the use of statin and the occurrence of delirium in each group, while taking into account the properties of statins. Results Comparisons between statin and non-statin patient groups revealed that only in group 2, patients who were administered statin showed significantly higher occurrence of delirium (p=0.004, odds ratio [OR]=1.58) compared to the patients who did not receive statin. Regardless of whether statins were lipophilic (p=0.036, OR=1.47) or hydrophilic (p=0.032, OR=1.84), the occurrence of delirium was higher only in patients from group 2. Although both lipophilic and hydrophilic statins in group 2 were associated with delirium, neither showed a greater association than the other. Conclusions The use of statins may be associated with the increases in the risk of delirium occurrence in patients with mild to moderate disease severity, irrespective of statin properties, as revealed by results from a large cohort study.

Factors Affecting Delirium in ICU Patients

“…Furthermore, delirium severity was higher among patients on a ventilator and among patients who had been on mechanical ventilation for more than 6 days. This finding is consistent with the findings of Ahn et al [4], where the percentage of patients on a ventilator was higher in the delirium group than the no-delirium group, and that of Kooken et al [13], where the delirium group was on mechanical ventilation longer on average than the no-delirium group. The mean number of catheters placed in our participants was 3.84, and the most common catheter was a Foley catheter, followed by the arterial line, central line, and nasogastric tube.…”

“…The results showed that ICU LOS, the number of physical restraints, GCS score, and BUN significantly predicted delirium. ICU LOS has been reported in previous studies to be longer in delirium patients than no-delirium patients [13,38] and to be a predictor of delirium [4,13]. An ICU has lights on 24 h a day, has no windows, and treatment and tests are performed around the clock.…”

“…The incidence of delirium in the intensive care unit (ICU) ranges from 7.4-81.7% [3][4][5], and delirium most commonly occurs on days 1-2 after ICU admission [6]. Furthermore, delirium impacts patients' prognosis by extending the duration of mechanical ventilation and increasing the mortality rate among ICU patients [7].…”

“…Delirium is influenced by patient history pre-hospitalization factors such as age, education level, visual acuity, and hearing impairment [12], and the use of psychiatric medications before hospitalization [13]. Factors that trigger delirium after hospital admission include the acute physiology and chronic health evaluation II (APACHE II) score, the Sequential Organ Failure Assessment (SOFA) score, physical restraints, use of a ventilator, hypoalbuminemia, acidosis, length of stay in the ICU, use of anticonvulsants, orthopedic surgery, postoperative use of antipsychotics, a nasogastric tube, a urinary catheter, and the insertion and retaining of a central venous catheter [4,6,10,14,15]. In addition, falls are significantly correlated with delirium [16] Pain scores in delirium patients are higher than those in no-delirium patients [17,18].…”