title: The ratchet effect: dramatic and sustained changes in health care utilization following admission to hospital with chronic disease.
abstract: OBJECTIVE
  To describe the previously unexamined association between admissions to hospital with chronic disease and changes in all-cause health service utilization over time.
  
  
  METHODS
  A cohort study examining the population of Western Australia with hospitalizations for chronic disease from 2002 to 2010. A "rolling" clearance period is used to define "cardinal events," that is, a disease-specific diagnosis upon hospital admission, where such an event has not occurred in the previous 2 years. Changes in the rate of cardinal events associated with diagnoses of heart failure, type 2 diabetes, chronic obstructive pulmonary disease, cataract with diabetes, asthma, and dialysis are examined. Health service utilization (defined as inpatient days or emergency department presentations) 6 years preceding and 4 years following such events is presented.
  
  
  RESULTS
  Cardinal events make up 40%-60% of all chronic disease admissions. A previously undescribed ratchet effect following cardinal events specifically associated with type 2 diabetes, heart failure, and chronic obstructive pulmonary disease is observed. This involves a 2- to 3-fold increase in inpatient days and emergency department presentations that are sustained for at least 4 years.
  
  
  CONCLUSIONS
  Cardinal events represent an important reference point to understand the impact of chronic disease on health service utilization. Events that herald such a marked transition in health service demand have not been previously described.
authors: *School of Primary, Aboriginal and Rural Health Care, Faculty of Medicine, Dentistry and Health Sciences †School of Mathematics and Statistics, Faculty of Engineering, Computing and Mathematics ‡School of Population Health, Faculty of Medicine, Dentistry and Health Sciences, University of Western Australia, Crawley, WA §Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia.
authors: David
authors: D
authors: Whyatt
authors: Raji
authors: R
authors: Tenneti
authors: Julie
authors: J
authors: Marsh
authors: Sarah E
authors: SE
authors: Bolt
authors: Anna
authors: A
authors: Kemp
authors: Laura
authors: L
authors: Firth
authors: Kevin
authors: K
authors: Murray
authors: Berwin
authors: B
authors: Turlach
authors: Alistair
authors: A
authors: Vickery
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000628:therapy; D002386:Cataract / Q000628:therapy; D002908:Chronic Disease / Q000628:therapy*; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000628:therapy; D003956:Dialysis / Q000706:statistics & numerical data*; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006296:Health Services / Q000706:statistics & numerical data*; D006301:Health Services Needs and Demand / Q000706:statistics & numerical data*; D006333:Heart Failure / Q000628:therapy; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010343:Patient Admission / Q000706:statistics & numerical data*; D029424:Pulmonary Disease, Chronic Obstructive / Q000628:therapy; D051437:Renal Insufficiency / Q000628:therapy; D014904:Western Australia