Association Between Comorbid Psychiatric Disorders and Hospital Resource Utilization in Physically Ill Pediatric Inpatients: A Case-Matched Analysis

Abstract Objective To understand differences in hospital length of stay and costs associated with the presence of a comorbid psychiatric disorder among physically ill inpatients within a publicly funded pediatric hospital. Method A retrospective observational design using administrative data on physically ill inpatients 2 to 18 years old admitted over a five-year period (n = 54,316 admissions). Records with (n = 4,953) and without (n = 49,363) documented comorbid psychiatric disorder were compared for differences in baseline characteristics. To optimize balance of measured covariates, those with comorbid psychiatric disorders were matched on Propensity Score, Case Mix and Elixhauser comorbidities, resulting in 4,371 pairs of inpatients with and without comorbid psychiatric disorder. Differences in length of stay and total hospital costs were assessed using Generalized Estimating Equation models on matched patients. Results Unmatched analyses demonstrated that inpatient admissions with comorbid psychiatric disorders were associated with higher occurrence of previous hospitalizations (69.2% vs. 55.0%), unscheduled admissions (66.9% vs. 60.9%), medical admissions (75.6% vs. 52.7%), urgent admissions (62.5% vs. 56.2%), and Elixhauser comorbidities (69.0% vs. 39.0%), with standardized differences > |0.1|. Matched analyses demonstrated a 9.6% longer length of stay (95% CI: 5.7-13.7; p Conclusion The complexity of inpatients with a comorbid psychiatric disorder, in conjunction with the approximate 10% increase in hospital resource utilization, highlights the need for innovative models of clinical care and research directed at improving patient outcomes and reducing hospital costs.