Association Between Intensive Care Unit Utilization During Hospitalization and Costs, Use of Invasive Procedures, and Mortality.

Importance: Maximizing the value of critical care services requires understanding the relationship between intensive care unit (ICU) utilization, clinical outcomes, and costs.

Objective: To examine whether hospitals had consistent patterns of ICU utilization across 4 common medical conditions and the association between higher use of the ICU and hospital costs, use of invasive procedures, and mortality.

Design, Setting, and Participants: Retrospective cohort study of 156 842 hospitalizations in 94 acute-care nonfederal hospitals for diabetic ketoacidosis (DKA), pulmonary embolism (PE), upper gastrointestinal bleeding (UGIB), and congestive heart failure (CHF) in Washington state and Maryland from 2010 to 2012. Hospitalizations for DKA, PE, UGIB, and CHF were identified from the presence of compatible International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Multilevel logistic regression models were used to determine the predicted hospital-level ICU utilization during hospitalizations for the 4 study conditions. For each condition, hospitals were ranked based on the predicted ICU utilization rate to examine the variability in ICU utilization across institutions.

Main Outcomes and Measures: The primary outcomes were associations between hospital-level ICU utilization rates and risk-adjusted hospital mortality, use of invasive procedures, and hospital costs.

Results: The 94 hospitals and 156 842 hospitalizations included in the study represented 4.7% of total hospitalizations in this study. ICU admission rates ranged from 16.3% to 81.2% for DKA, 5.0% to 44.2% for PE, 11.5% to 51.2% for UGIB, and 3.9% to 48.8% for CHF. Spearman rank coefficients between DKA, PE, UGIB, and CHF showed significant correlations in ICU utilization for these 4 medical conditions among hospitals (ρ ≥ 0.90 for all comparisons; P < .01 for all). For each condition, hospital-level ICU utilization rate was not associated with hospital mortality. Use of invasive procedures and costs of hospitalization were greater in institutions with higher ICU utilization for all 4 conditions.

Conclusions and Relevance: For medical conditions where ICU care is frequently provided, but may not always be necessary, institutions that utilize ICUs more frequently are more likely to perform invasive procedures and have higher costs but have no improvement in hospital mortality. Hospitals had similar ICU utilization patterns across the 4 medical conditions, suggesting that systematic institutional factors may influence decisions to potentially overutilize ICU care. Interventions that seek to improve the value of critical care services will need to address these factors that lead clinicians to admit patients to higher levels of care when equivalent care can be delivered elsewhere in the hospital.