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The Cost-Effectiveness of Interventions in Health and Medicine

The Cost-Effectiveness of Interventions in Health and Medicine. William H. Herman, M.D., M.P.H. University of Michigan. Rationale for conducting cost-effectiveness analyses How is cost-effectiveness assessed? What is the cost-effectiveness of diabetes prevention?.

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The Cost-Effectiveness of Interventions in Health and Medicine

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  1. The Cost-Effectiveness of Interventions in Health and Medicine William H. Herman, M.D., M.P.H. University of Michigan

  2. Rationale for conducting cost-effectiveness analyses • How is cost-effectiveness assessed? • What is the cost-effectiveness of diabetes prevention?

  3. Barriers to diffusion of new medical treatments • Patient • Provider • System

  4. Patient level barriers • Demographic (age, gender, race) • Socioeconomic position (education, income) • Health status (including depression) • Self-efficacy • Cost

  5. Provider level barriers • Demographics (age, training, CME, experience) • Knowledge of guidelines and critical pathways • Attitudes to innovation • Opinions of key opinion leaders • Peer practices • Cost

  6. System level barriers • Practice structure and organization • Information systems • Time barriers • Cost

  7. Why perform CEAs? • Resources are limited • Choices must be made • Choices should consider costs and outcomes

  8. Value for Money

  9. Essential Elements of Economic Analyses of Health-Care Programs • Type of analysis • Perspective • Type and definition of costs • Description and valuation of outcomes • Choice of comparator • Modeling • Discounting • Sensitivity analyses

  10. Types of Economic Analyses • Descriptive cost analysis • Cost-benefit • Cost-effectiveness • Cost-utility

  11. Perspective of Economic Analyses • Payer • Society

  12. Type of Costs • Direct medical • Direct nonmedical • Indirect

  13. Definition of Direct Medical Costs • Cost of intervention • Cost of side-effects of intervention • Cost of outcomes

  14. Description and Valuation of Outcomes • Beneficial outcomes produced • Adverse outcomes averted

  15. Outcomes • Clinical • Years of life • Quality-adjusted life-years

  16. QALY Quality-Adjusted Life-Year adjusts length of life for quality of life

  17. Quality-Adjusted Life-Year time in health state x quality of life in health state where quality of life = health utility 1.0 = excellent health 0 = death

  18. Calculation of QALYs 20 years of life/excellent health 20 x 1.0 = 20 QALYs 20 years of life/10 excellent health 10 with blindness (10 x 1.0) + (10 x 0.51) = 15.1 QALYs

  19. Approaches to Measuring Health Utilities • Standard gamble • Multiattribute utility models • Rating scales

  20. Multiattribute Utility Models • Health Utilities Index (HUI) • Quality of Well-Being Index (QWB) • EuroQol (EQ-5D)

  21. Choice of Comparator New therapy vs. ? all relevant alternatives? ? usual therapy? ? substandard therapy? ? placebo?

  22. Choice of Comparator Failure to compare a new therapy with a strong alternative will result in a deceptively favorable cost-effectiveness picture.

  23. Modeling When direct empirical data are not available, methods of imputation and extrapolation are used to estimate outcomes No model generates new data, it merely combines existing information within an explicit framework

  24. Discounting • Even in a world of zero inflation, there are advantages to receiving benefits earlier and incurring costs later. • Discounting adjusts future costs and benefits to current value.

  25. Sensitivity Analyses The values of one or more of the key parameters are varied singly or simultaneously to evaluate the robustness of the results to the underlying assumptions.

  26. What is the cost-effectiveness of diabetes prevention?

  27. Interventions Proven to Delay or Prevent the Development of Type 2 Diabetes Intervention % Risk Reduction Lifestyle (4 trials) 29-58% Metformin (2 trials) 26-31% Lifestyle & Metformin (1 trial) 28% Acarbose (1 trial) 25% Troglitazone (1 trial) 55% Rosiglitazone (1 trial) 60%

  28. DPP Study Population 3,234 subjects with impaired glucose tolerance (IGT) Fasting plasma glucose 95 - 125 mg/dl 2 hour plasma glucose 140 - 199 mg/dl Age > 25 years (mean 51 years) BMI > 24 kg/m2 (mean 34 kg/m2) 68% women 45% minorities

  29. DPP Interventions Lifestyle healthy, low-calorie, low-fat diet & physical activity of moderate intensity (brisk walking for  150 min/week) to achieve and maintain  7% loss of body weight 16 session core curriculum over 6 months then monthly follow-up Metformin 850 mg daily increasing to 850 mg twice daily standard lifestyle recommendations quarterly follow-up Placebo standard lifestyle recommendations

  30. Incidence of Diabetes Placebo (n=1082) Metformin (n=1073, p<0.001 vs. Placebo) Lifestyle (n=1079, p<0.001 vs. Metformin , p<0.001 vs. Placebo) Risk reduction 31% by metformin 58% by lifestyle The DPP Research Group, NEJM 346:393-403, 2002

  31. Analyses Health system perspective Cost per Quality-Adjusted Life-Year (QALY) Lifetime time horizon Interventions as implemented in the DPP Year 2000 US dollars DPP. Ann Intern Med 142:323, 2005

  32. Data Sources Treatment of IGT Treatment of Diabetes Costs DPP Cost Model Quality of Life DPP Quality of Life Model Health Outcomes DPP Type 2 Diabetes Model DPP. Ann Intern Med 142:323, 2005

  33. Annual Direct Medical Costs in a Man Progressing from IGT to Diabetes with Complications Brandle et al. Diabetes Care 26:2300, 2003.

  34. Health Utility Scores in a Man Progressing from IGT to Diabetes with Complications Coffey et al. Diabetes Care 25:2238, 2002.

  35. Diabetes Cost-Effectiveness Model Markov model structure Follows a patient cohort from diagnosis of IGT to death IGT transition probabilities based on DPP Diabetes, microvascular and macrovascular transition probabilities based on UKPDS and literature Assumes 10 year interval between DPP onset and UKPDS clinical diagnosis of type 2 diabetes mellitus Tracks costs, QALYs, disease progression, 5 complications, and survival CDC Diabetes Cost-effectiveness Group. JAMA 287:2542, 2002

  36. Simulated Cumulative Incidence of Diabetes in the DPP 8% 20% Herman et al. Ann Intern Med 142:323, 2005

  37. Simulated Lifetime Clinical Outcomes in the DPP Outcome Lifestyle Metformin Placebo Diabetes (%) 63 75 83 Blindness (%) 3 5 6 ESRD (%) 0.6 0.8 1.0 Amputation (%) 1.3 1.6 1.9 Stroke (%) 19 21 21 CHD (%) 39 41 42 Life expectancy (yrs) 24.7 24.3 24.1 Herman et al. Ann Intern Med 142:323, 2005

  38. IGT Intervention -Summary Lifetime Outcomes* Outcome Lifestyle Metformin Placebo Lifetime Costs $51,974 $55,261 $51,339 Lifetime QALYs 10.89 10.45 10.32  Cost v. Pbo $635 $3,922 ——  QALY v. Pbo 0.57 0.13 ——  Cost/  QALY $1,124 $31,286 —— * costs and QALYs discounted at 3% per year Herman et al. Ann Intern Med 142:323, 2005

  39. How Attractive Does a New Technology Have to be to Warrant Adoption and Utilization? more costly more effective & more costly less effective & more costly Decrease in QALYs Increase in QALYs less effective & less costly more effective & less costly less costly

  40. Distribution of Cost-Effectiveness Ratios for Preventive Measures and Treatments for Existing Conditions Cohen JT. N Engl J Med 2008; 358:661-663

  41. Cost-Effectiveness of Selected Interventions in the Medicare Population PJ Neumann. N Engl J Med 2005; 353:1516-1522

  42. How Attractive Does a New Technology Have to be to Warrant Adoption and Utilization? more costly $100,000/QALY $20,000/QALY Decreased QALYs Increased QALYs $20,000/QALY $100,000/QALY less costly

  43. Conclusion Interventions for diabetes prevention represent a good value for money in people with IGT.

  44. But... • An alternative analysis suggested a substantially higher cost per QALY-gained for the lifestyle intervention ($200,000 per QALY-gained). Eddy DM. Ann Intern Med 2005; 143:251-264

  45. Purpose To assess the cost-effectiveness of the lifestyle and metformin interventions relative to the placebo intervention with an intent-to-treat analysis spanning the combined 10 years of DPP/DPPOS.

  46. Background • The DPPOS followed participants for an additional 7 years during which time those in the lifestyle and metformin interventions were encouraged to continue those interventions. • During DPPOS, lifestyle participants received extra lifestyle support and all participants were offered a 16 session group lifestyle intervention and 4 healthy lifestyle program sessions per year. • A recent intent-to-treat analysis demonstrated a persistent benefit of the lifestyle and metformin interventions on the incidence of type 2 diabetes for at least 10 years after randomization.

  47. Cumulative Incidence of Diabetes during DPP/DPPOS 10-year incidence 52% 47% Risk reduction vs Placebo DPP – 3 years Lifestyle 58% Metformin 31% 42% Risk reduction vs Placebo DPP/DPPOS – 10 years Lifestyle 31% Metformin 19% DPP Research Group. Lancet. 2009; 374:1677-1686

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