title: Cost effectiveness and value of information analyses of islet cell transplantation in the management of 'unstable' type 1 diabetes mellitus.
abstract: BACKGROUND
  Islet cell transplantation is a method to stabilize type 1 diabetes patients with hypoglycemia unawareness and unstable blood glucose levels by reducing insulin dependency and protecting against severe hypoglycemia through restoring endogenous insulin secretion. This study analyses the current cost-effectiveness of this technology and estimates the value of further research to reduce uncertainty around cost-effectiveness.
  
  
  METHODS
  We performed a cost-utility analysis using a Markov cohort model with a mean patient age of 49 to simulate costs and health outcomes over a life-time horizon. Our analysis used intensive insulin therapy (IIT) as comparator and took the provincial healthcare provider perspective. Cost and effectiveness data for up to four transplantations per patient came from the University of Alberta hospital. Costs are expressed in 2012 Canadian dollars and effectiveness in quality-adjusted life-years (QALYs) and life years. To characterize the uncertainty around expected outcomes, we carried out a probabilistic sensitivity analysis within the Bayesian decision-analytic framework. We performed a value-of-information analysis to identify priority areas for future research under various scenarios. We applied a structural sensitivity analysis to assess the dependence of outcomes on model characteristics.
  
  
  RESULTS
  Compared to IIT, islet cell transplantation using non-generic (generic) immunosuppression had additional costs of $150,006 ($112,023) per additional QALY, an average gain of 3.3 life years, and a probability of being cost-effective of 0.5 % (28.3 %) at a willingness-to-pay threshold of $100,000 per QALY. At this threshold the non-generic technology has an expected value of perfect information (EVPI) of $260,744 for Alberta. This increases substantially in cost-reduction scenarios. The research areas with the highest partial EVPI are costs, followed by natural history, and effectiveness and safety.
  
  
  CONCLUSIONS
  Current transplantation technology provides substantial improvements in health outcomes over conventional therapy for highly selected patients with 'unstable' type 1 diabetes. However, it is much more costly and so is not cost-effective. The value of further research into the cost-effectiveness is dependent upon treatment costs. Further, we suggest the value of information should not only be derived from current data alone when knowing that this data will most likely change in the future.
authors.affiliation: Department of Emergency Medicine, University of Alberta, 736 University Terrace Building, 8303 - 112 Street, Edmonton, AB, T6G 2T4, Canada. wallner@ualberta.ca.
authors.forename: Klemens
authors.initials: K
authors.lastname: Wallner
authors.affiliation: Clinical Islet Transplant Program, Alberta Diabetes Institute, University of Alberta, 2000 College Plaza, 8215 - 112 Street, Edmonton, AB, T6G 2C8, Canada.|Department of Surgery, University of Alberta, Edmonton, AB, Canada.
authors.forename: A M James
authors.initials: AM
authors.lastname: Shapiro
authors.affiliation: Clinical Islet Transplant Program, Alberta Diabetes Institute, University of Alberta, 2000 College Plaza, 8215 - 112 Street, Edmonton, AB, T6G 2C8, Canada.|Division of Endocrinology and Metabolism, Department of Medicine, University of Alberta, Edmonton, Canada.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Senior
authors.affiliation: Department of Emergency Medicine, University of Alberta, 736 University Terrace Building, 8303 - 112 Street, Edmonton, AB, T6G 2T4, Canada.
authors.forename: Christopher
authors.initials: C
authors.lastname: McCabe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003362:Cost-Benefit Analysis; D000068598:Data Accuracy; D048909:Diabetes Complications / Q000453:epidemiology; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis / Q000191:economics* / Q000453:epidemiology / Q000628:therapy*; D018450:Disease Progression; D005260:Female; D006801:Humans; D016381:Islets of Langerhans Transplantation / Q000191:economics / Q000592:standards / Q000706:statistics & numerical data; D008017:Life Expectancy; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011379:Prognosis; D019057:Quality-Adjusted Life Years; D016896:Treatment Outcome
keywords: Beta cells; Cost-effectiveness analysis; Edmonton protocol; Intensive insulin therapy; Islet transplantation; Markov model; Scenario analysis; Type 1 diabetes; Value of information