Development and Validation of a Model for Predicting Inpatient Hospitalization

Background: Hospitalizations are costly for health insurers and society. Objectives: To develop and validate a predictive model for acute care hospitalization from administrative claims for a population including all age groups. Research Design: We constructed a retrospective cohort study using a US health plan claims database, including annual person-level files with demographic markers, and morbidity and utilization measures. We developed and validated the model using separate data. Participants: The validation sample included 4.7 million persons enrolled for at least 6 months in 2006 and 1 or more months in 2007. Measures: Risk factors and outcome variables were obtained from administrative claims data using the Adjusted Clinical Group (ACG) system. Utilization variables were added, and models were fitted with multivariate logistic regression. Results: A 3.2% of patients had a hospitalization during a 1-year period, and 20% of patients who had been hospitalized during the previous year were rehospitalized. Effect sizes of risk factors were modest with odds ratios