Substance dependence and psychiatric disorders are related to outcomes in a mixed ICU population

Substance dependence disorders are common in hospitalized patients and are associated with poor recovery. We compared mortality and discharge disposition in critically ill patients with and without substance dependence and patients with and without psychiatric disorders. We also compared the prevalence of substance dependence and psychiatric disorders to population data.

All medical records of shock trauma intensive care unit (ICU) patients (mixed medical and surgical) at LDS Hospital were reviewed for pre-critical illness alcohol dependence, drug dependence, and psychiatric disorders.

There were 742 critically ill patients of whom 54% were male, acute respiratory distress syndrome developed in 5.5% and hospital mortality was 21%. The mean acute physiology and chronic health evaluation II scores were 16.5 ± 7.9, sequential organ failure assessment scores were 6.7 ± 4.2, duration of mechanical ventilation was 5 ± 6.2 days, ICU length of stay (LOS) was 7.3 ± 10.1 days, hospital LOS was 12.3 ± 12.9 days. Multivariable regression analyses found psychiatric disorders predicted higher hospital mortality (Odds ratio = 1.50), but was not statistically significant (p = 0.08); substance dependence predicted shorter hospital LOS (R ²  = 0.08, p = 0.01) after controlling for covariates. There was a higher prevalence of substance dependence compared to Utah (p < 0.001) and US population data (p < 0.001). The prevalence of psychiatric disorders was significantly lower in our patients compared to US population data (19 vs. 26%, p < 0.001).

Our data suggest that substance dependence increases hospital LOS and that patients with drug or alcohol dependence are at higher risk for ICU admission compared to the general population.