(1006) Association Between Medication Regimen Complexity and ICU Mortality in a Large Cohort

Introduction: Characterizing the relationship between intensive care unit (ICU) medication use and mortality is important for ICU prediction models to optimize pharmacotherapy during critical illness. The objective of this study was to characterize the association between MRC-ICU and ICU mortality and explore how MRC-ICU may improve baseline severity of illness prediction models.

Methods: This was an observational cohort study of adult ICUs including a random sample of 991 adults admitted ≥24 hours between 10/2015 to 10/2020. The primary outcome of mortality was assessed by area under the receiver operating characteristic (AUROC) via regression modeling. Baseline demographic features (e.g., age, sex, ICU type, medication regimen complexity as measured by the MRC-ICU) were collected and severity of illness (based on worst values within the first 24 hours of ICU admission) was characterized using both the Acute Physiology and Chronic Health Evaluation (APACHE II) and the Sequential Organ Failure Assessment (SOFA) score.

Results: In univariate analysis, every one-point increase in the average 24-hour MRC-ICU score was associated with a 7% increase in hospital mortality [Odds Ratio (OR) 1.07, 95% confidence interval (CI) 1.04-1.09, p < 0.001]. After controlling for baseline APACHE-II score and SOFA score, the average daily MRC-ICU score was associated with a 6% decrease in hospital mortality (OR 0.94, 95% CI 0.90-0.99, p-value = 0.020). The AUROC was 0.81 for the model including both 24-hour APACHE II and 24-hour SOFA and MRC-ICU compared to 0.76 to SOFA and APACHE II alone.

Conclusions: Medication regimen complexity appears to influence mortality in ICU patients, and prediction models incorporating drug information showed modest improvement in prediction.