Comparison of Methods to Define High Use of Inpatient Services Using Population-Based Data
BACKGROUND: A variety of methods have been proposed to define “high users” of inpatient services, which may have implications for targeting subgroups for intervention.
OBJECTIVE: To compare 3 common definitions of high inpatient service use and their influence on patient capture, outcomes, and inpatient burden.
DESIGN, SETTING, AND PATIENTS: Cross-sectional population-level study of 219,106 adults in Alberta, Canada, with ≥1 hospitalization from April 1, 2012, to March 31, 2013.
MEASUREMENTS: We defined “high use” based on the upper 5th percentile of the population by 3 definitions: (1) number of inpatient episodes (≥3 hospitalizations/year), (2) cumulative length of stay (≥56 days in hospital/year), and (3) cumulative cost based on hospitalization resource intensity weights (≥ $63,597 Canadian dollars/year). Clinical characteristics, health outcomes, and overall health burden were compared across definitions and stratified by age.
RESULTS: Of that population, 10.3% of individuals were common to all definitions. High users based on number of inpatient episodes were more likely to be admitted for acute conditions, with most high users based on length of stay admitted for mental health-related conditions, while those based on costs were more likely to have hospitalizations resulting in death (9.3%). High-episode individuals accounted for 16.6% of all inpatient episodes, high-length of stay individuals for 46.4% of all hospital days, and high-cost individuals for 38.9% of total cost.
CONCLUSIONS: Three definitions of high users of inpatient services captured significantly different groups of patients. This has implications for targeting subgroups for intervention and highlights important considerations for selecting the most suitable definition for a given objective.
© 2017 Society of Hospital Medicine
CONCLUSIONS
Definitions of high use of inpatient services based on number of inpatient episodes, days spent in hospital, and total hospital costs identify patient populations with different characteristics and differ substantially in their impact on health outcomes and inpatient burden. These results highlight the need for careful consideration of the context of the study or intervention and the implications of selecting a specific definition of high inpatient use at study conception. Ultimately, the performance of an intervention in high-use populations is likely to be conditional on the fit of the patient population generated by the chosen definition of high inpatient use to the objectives of a study.
Acknowledgments
This study is based in part on data provided by Alberta Health and Alberta Health Services. The interpretation and conclusions are those of the researchers and do not represent the views of the Government of Alberta. Neither the Government of Alberta nor Alberta Health express any opinion in relation to this study.
Disclosure
Dr. Hemmelgarn is supported by the Roy and Vi Baay Chair in Kidney Research. Dr. Manns is supported by the Svare Professorship in Health Economics and by a Health Scholar Award by Alberta Innovates Health Solutions (AIHS). Dr. Tonelli is supported by the David Freeze chair in Health Services Research. The Interdisciplinary Chronic Disease Collaboration is funded by AIHS—Collaborative Research and Innovation Opportunity (CRIO) Team Grants Program.
