title: Patterns of health care use in a high-cost inpatient population in Ottawa, Ontario: a retrospective observational study.
abstract: BACKGROUND
  A small proportion of patients account for the majority of health care spending. We used detailed clinical and administrative data to explore clinical characteristics, patterns of health care use and changes in cost profiles over time among high-cost inpatients in an acute tertiary care hospital in Ottawa, Ontario.
  
  
  METHODS
  We identified all people who had 1 or more inpatient admissions to The Ottawa Hospital between Apr. 1, 2009, and Mar. 31, 2012. We calculated the direct inpatient costs using case-costing information to categorize patients into persistently high-cost, episodic high-cost and non-high-cost groups. Within each group, we used discharge abstracts to measure encounter-level characteristics and patterns of inpatient health care use over time. We also developed transition matrices to explore how inpatient costing states changed over time.
  
  
  RESULTS
  During the study period, 100 178 patients had 132 996 hospital admissions. Hospital spending was often limited to a single year for most of the patients (90.2%), with only a small proportion (7.4%) of patients remaining in the high-cost group in the subsequent year. Patients in the persistently (n = 236) and episodic (n = 5062) high-cost groups were often older, had medically complex conditions and generated most of the costs from nursing care and intensive care. Compared with patients in the other cost groups, those in the persistently high-cost group were more likely to have multiple readmissions (43.4%) and multiple placements in an alternate level of care (19.0%) and were high users of health care services outside of the hospital setting.
  
  
  CONCLUSIONS
  Hospital spending was often limited to a single year for most patients, and only a small proportion of patients remained in the high-cost group in the subsequent year. These persistently high-cost patients had medically complex conditions and often required expensive care. A greater understanding of the circumstances that result in persistent hospital spending remains an area for future work, including an exploration of the potential barriers impeding efficient transition out of acute care for high-risk patients.
authors.affiliation: Department of Clinical Epidemiology, Ottawa Hospital Research Institute, Ottawa, Ont.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Ronksley
authors.affiliation: Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ont.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: McKay
authors.affiliation: Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ont. ; Department of Medicine, University of Ottawa, Ottawa, Ont.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Kobewka
authors.affiliation: Department of Medicine, University of Ottawa, Ottawa, Ont.
authors.forename: Sunita
authors.initials: S
authors.lastname: Mulpuru
authors.affiliation: Department of Clinical Epidemiology, Ottawa Hospital Research Institute, Ottawa, Ont. ; Department of Medicine, University of Ottawa, Ottawa, Ont.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Forster
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