UCSF Global Health Economics Colloquium

Cost-Effectiveness Workshop

Kisumu
20 January 2014
Purpose of CEA Workshop
• Basic understanding of CEA concepts &
methods
• Initial application to an issue of your
choosing...
Purpose of CEA
• “Opportunity cost” is a governing concept: resources
used for one purpose cannot be used for another.

• ...
CEA Core Approach
• Incremental cost per standardized unit of health
gain

- E.g., per death averted or life-year gained
•...
Key CEA outcome metric: ICER
• ICER – Incremental Cost-Effectiveness Ratio
• Δ costs / Δ health outcomes
– Δ means the dif...
ICER Numerator
• Net costs = program costs adjusted for resulting
changes in medical costs
• Still, A vs B: net cost A – n...
ICER Denominator
• Difference between A and B in
o Natural health events (eg new infections or deaths
averted), or

o DALY...
“What is a „DALY’ anyway?”
• DALY = Disability-Adjusted Life-Years
• Summary measure of disease burden
• Sum of:
o Mortali...
“The DALY Show” video
(if possible)

9
Disability weights: applications
For Descriptive Use (burden of disease):
 Disability Weights must reflect the relative s...
 Argument for using DALY DWs is that they are
derived through same process and are available
for a large number of diseas...
Disability Weight: sources
1.

IHME Global Health Data Exchange (GHDx)

http://ghdx.healthmetricsandevaluation.org/record/...
Disability Weights: sources
2.

The Lancet 2012 paper

Assignment: find the disability weights for HIV (not on
ART)
A Basic CEA Results Table
Option

Net cost

Δ cost

DALYs

Δ
DALYs

ICER
($ per DALY
averted)

No
therapy

$10,000

n/a

4...
A Basic CEA Results Table
Option

Net cost

Δ cost

DALYs

Δ
DALYs

ICER
($ per DALY
averted)

No
therapy

$10,000

n/a

4...
CEA Results Table – Negative ICER?!
Option

Net cost

Δ cost

DALYs

Δ
DALYs

(Δ $ / Δ DALY)

ICER

No therapy

$10,000

n...
CEA Results Table – “Dominance”
Option

Net cost

Δ cost

DALYs

Δ
DALYs

(Δ $ / Δ QALY)

ICER

No therapy

$10,000

n/a

...
CEA Table with Multiple Comparisons
Option

Net cost

Δ cost

DALYs

Δ
DALYs

(Δ $ / Δ DALY)

ICER

No therapy

$10,000

n...
Introducing sensitivity analyses - Why do
them?
• All CEAs have substantial uncertainty.

• Sensitivity analyses deal with...
One-way SA: Screening for gestational diabetes
Tornado diagram showing sensitivity of ICER to 16 key inputs. CCMH,
Chennai...
Multi-Way SA: Screening for gestational diabetes
20,000-trial Monte Carlo simulation, CCMH, Chennai, India. Distribution o...
Analytic horizon – timing is everything
• What time period to portray?
– 30 days? 1 year? 5 years? A lifetime?

• Not stan...
Analytic Time Line
Reference Case for CEA
• $ per QALY gained or DALY averted
• Societal (all payers), direct medical costs
• Discount future...
CEA Research Questions –
Examples

25
CEA Example A – Research Questions
Cost-effectiveness of a mobile camp for adult male
circumcision in rural Zambia

• RQ1:...
CEA Example A – RQ1
Cost-effectiveness of a mobile camp for adult male
circumcision in rural Zambia

• RQ1: What is the co...
CEA Example A – RQ2
Cost-effectiveness of a mobile camp for adult male
circumcision in rural Zambia

• RQ2: How many HIV i...
CEA Example A – RQ3
Cost-effectiveness of a mobile camp for adult male
circumcision in rural Zambia

• RQ3: What is the in...
Introducing decision trees
• Graphically portrays the decision & its effects
• Three major components:
– The action option...
A Basic Decision Tree
Voluntary adult male circumcision for HIV prevention in rural Kenya
HIV infection
0.4
No camp
No HIV...
Adding Health
Outcomes

New HIV
infections
Per person

DALYs due
to new HIV
infections
7

HIV infection
0.4

40

280

No H...
Adding
Intervention
Costs

New HIV
infections
Per person

HIV infection
0.4

40

DALYs due
to new HIV
infections

Cost of ...
Adding
Medical Care
Costs

New HIV
infections
Per person

DALYs due
Cost of MC
to new HIV
Camp
infections

Cost of HIV
med...
And Finally
– Results!

New HIV
infections
Per person

DALYs due
Cost of MC
to new HIV
Camp
infections

Cost of HIV
medica...
CEA Example B – Specific Aims
Cost-effectiveness of adherence counseling for HIV
anti-retroviral therapy (ART) in a primar...
CEA Example B – Specific Aim 1
Cost-effectiveness of adherence counseling for HIV
anti-retroviral therapy (ART) in a prima...
CEA Example B – Specific Aim 2
Cost-effectiveness of adherence counseling for HIV
anti-retroviral therapy (ART) in a prima...
CEA Example B – Specific Aim 3
Cost-effectiveness of adherence counseling for HIV
anti-retroviral therapy (ART) in a prima...
Cost-effectiveness of adherence counseling for ART, primary care clinic in rural India, in RCT
Simplified tree

Health out...
What cost-effectiveness research
question are you interested in?
• What is:
– the intervention?
– the comparator?
• What o...
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Comparative Effectiveness: UCSF East Africa Global Health -Kisumu 2014

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  • This dataset provides the disability weights with uncertainty intervals for 220 unique health states used to estimate non-fatal health outcomes in the GBD 2010 Study. The data were published in The Lancet in December 2012 in the paper “Common values in assessing health outcomes from disease and injury: disability weights measurement study for the Global Burden of Disease Study 2010.”
  • Comparative Effectiveness: UCSF East Africa Global Health -Kisumu 2014

    1. 1. UCSF Global Health Economics Colloquium Cost-Effectiveness Workshop Kisumu 20 January 2014
    2. 2. Purpose of CEA Workshop • Basic understanding of CEA concepts & methods • Initial application to an issue of your choosing • Foundation for further development of ideas and projects 2
    3. 3. Purpose of CEA • “Opportunity cost” is a governing concept: resources used for one purpose cannot be used for another. • To foster efficient deployment of limited health resources, we measure “opportunity costs” • Assess the efficiency of available interventions to achieve agreed health goals, e.g., – Less frequent vs. more frequent screening; – Mobile vs. fixed facility service delivery; – More vs. less intensive treatment. • Examples from comparisons of interest to you 3
    4. 4. CEA Core Approach • Incremental cost per standardized unit of health gain - E.g., per death averted or life-year gained • For specified interventions; always compared with other courses of action (standard of care, other interventions) • Is the inverse of (and equivalent to) health gain per increment of spending
    5. 5. Key CEA outcome metric: ICER • ICER – Incremental Cost-Effectiveness Ratio • Δ costs / Δ health outcomes – Δ means the difference between actions A and B • ICER = [Cost A – Cost B] / [LifeYears A – LifeYears B] • Incorrect: Cost A / LifeYears A. You need a comparator. What are the incremental LYs or QALYs (or DALYs averted)? Option Net cost Δ cost QALYs Δ QALYs ICER Drug A $12,000 ?? 4.0 ?? ?? 5
    6. 6. ICER Numerator • Net costs = program costs adjusted for resulting changes in medical costs • Still, A vs B: net cost A – net cost B • Medical costs can fall (averted disease) or rise (identified or induced need for care) 6
    7. 7. ICER Denominator • Difference between A and B in o Natural health events (eg new infections or deaths averted), or o DALYs (disease burden, want to avert), or o QALYs (health, want to gain) 7
    8. 8. “What is a „DALY’ anyway?” • DALY = Disability-Adjusted Life-Years • Summary measure of disease burden • Sum of: o Mortality (years lost due to premature death) + o Morbidity (disability weight * duration in years). • Opposite of QALY (measure of health) • In global health DALYs used more than QALYs QALY? DALY? Let’s call the whole thing off (someday)! 8
    9. 9. “The DALY Show” video (if possible) 9
    10. 10. Disability weights: applications For Descriptive Use (burden of disease):  Disability Weights must reflect the relative severity of the consequences of different disease and disease stages  Universal across time and over the globe For Evaluative Use (cost-effectiveness)  Adjust time lived for level of disability from diseases of interest other causes of disability  Measurement of non-fatal benefit of interventions may involve modest changes in severity  More demands on accuracy of level of severity
    11. 11.  Argument for using DALY DWs is that they are derived through same process and are available for a large number of diseases and health states that are a consequence of disease  QALYs rely on utility weights: a difference between two groups on a scale measuring the Quality of Life is translated into a utility weight  QALY ≠ QALY ≠ QALY if utility weights are plucked from disparate studies using different QoL instruments and different methods of translating the QoL scores into a utility value
    12. 12. Disability Weight: sources 1. IHME Global Health Data Exchange (GHDx) http://ghdx.healthmetricsandevaluation.org/record/global-burdendisease-study-2010-gbd-2010-disability-weights
    13. 13. Disability Weights: sources 2. The Lancet 2012 paper Assignment: find the disability weights for HIV (not on ART)
    14. 14. A Basic CEA Results Table Option Net cost Δ cost DALYs Δ DALYs ICER ($ per DALY averted) No therapy $10,000 n/a 4.0 n/a n/a Drug A $12,000 ? 3.5 ? ? Net cost = Cost of intervention Adjusted for induced or averted health care costs 14
    15. 15. A Basic CEA Results Table Option Net cost Δ cost DALYs Δ DALYs ICER ($ per DALY averted) No therapy $10,000 n/a 4.0 n/a n/a Drug A $12,000 $2,000 3.5 0.5 $4,000 15
    16. 16. CEA Results Table – Negative ICER?! Option Net cost Δ cost DALYs Δ DALYs (Δ $ / Δ DALY) ICER No therapy $10,000 n/a 4.0 n/a n/a Drug A $12,000 $2,000 3.5 0.5 $4,000 Drug B $17,000 $5,000 ? 3.75 - 0.25 ? - $20,000 ? 16
    17. 17. CEA Results Table – “Dominance” Option Net cost Δ cost DALYs Δ DALYs (Δ $ / Δ QALY) ICER No therapy $10,000 n/a 4.0 n/a n/a Drug A $12,000 $2,000 3.5 0.5 $4,000 Drug B $17,000 $5,000 3.75 -0.25 Dominated “Dominance” = One option both cheaper and better than comparator No trade-off = No brainer Negative ICERs makes no sense. 17
    18. 18. CEA Table with Multiple Comparisons Option Net cost Δ cost DALYs Δ DALYs (Δ $ / Δ DALY) ICER No therapy $10,000 n/a 4.0 n/a n/a Drug A $12,000 $2,000 3.5 0.5 $4,000 Drug B $17,000 $5,000 3.75 -0.25 Dominated Drug C $18,000 $6,000 2.5 1.0 $6,000 Drug D $23,000 $5,000 3.0 -0.5 Dominated Array costs from lower to higher. Compare each option to next higher (non-dominated) option. Drug C vs. No therapy is inappropriate … … feasible intermediate options must be evaluated. No skipping allowed! 18
    19. 19. Introducing sensitivity analyses - Why do them? • All CEAs have substantial uncertainty. • Sensitivity analyses deal with uncertainty systematically, one input at a time and overall. • Convince audience that results are robust (if you can). • Show how results hinge on the value of certain inputs • Show how key uncertainties, however disquieting initially, actually do not affect findings in important ways. Sensitivity analysis is mandatory in a CEA. And interesting. And fun! 19
    20. 20. One-way SA: Screening for gestational diabetes Tornado diagram showing sensitivity of ICER to 16 key inputs. CCMH, Chennai, India. Inputs varied 50% - 150% of base-case values Marseille E et al. (2013). "The cost-effectiveness of gestational diabetes screening including prevention of type 2 diabetes: application of a new model in India and Israel." J Matern Fetal Neonatal Med. Presentation title Date
    21. 21. Multi-Way SA: Screening for gestational diabetes 20,000-trial Monte Carlo simulation, CCMH, Chennai, India. Distribution of ICER values and 90% CI. Input values had beta distributions with minima and maxima at 50% and 150% of base case values 21
    22. 22. Analytic horizon – timing is everything • What time period to portray? – 30 days? 1 year? 5 years? A lifetime? • Not standard … the rule is – capture important differences between action options – For treatment of a self-limited disease (i.e., trying to reduce severity for a few weeks), perhaps 30 days. – For an intervention with effects that decay by half each 6 months, perhaps 2-3 years – For management of a chronic disease, perhaps lifetime. • If in doubt, err toward longer time horizon … little extra work. 22
    23. 23. Analytic Time Line
    24. 24. Reference Case for CEA • $ per QALY gained or DALY averted • Societal (all payers), direct medical costs • Discount future spending & health events, 3% per year • Time horizon adequate to capture effects • Report currency, price date, conversions • Sensitivity analyses (evaluating uncertainty) 1. U.S. Preventive Services Task Force. 2. Consolidated Health Economic Evaluation Reporting Standards (CHEERS) statement, BMJ, 2013. 24
    25. 25. CEA Research Questions – Examples 25
    26. 26. CEA Example A – Research Questions Cost-effectiveness of a mobile camp for adult male circumcision in rural Zambia • RQ1: What is the cost of delivering adult male circumcision per 100 clients circumcised in this mobile camp? • RQ2: How many HIV infections and disability-adjusted life years (DALYs) will be averted per 100 individuals circumcised, in this population, over twenty years? • RQ3: What is the incremental cost per DALY averted in this population? 26
    27. 27. CEA Example A – RQ1 Cost-effectiveness of a mobile camp for adult male circumcision in rural Zambia • RQ1: What is the cost of delivering adult male circumcision per 100 clients circumcised in this mobile camp? Brief methods: Review program financial and service records for 12-month period, to quantify resources used, associated costs, and clients served. 27
    28. 28. CEA Example A – RQ2 Cost-effectiveness of a mobile camp for adult male circumcision in rural Zambia • RQ2: How many HIV infections and disability-adjusted life years (DALYs) will be averted per 100 individuals circumcised, in this population, over twenty years? Brief methods: Build a decision analysis model incorporating HIV epidemic projections with and without circumcision. 28
    29. 29. CEA Example A – RQ3 Cost-effectiveness of a mobile camp for adult male circumcision in rural Zambia • RQ3: What is the incremental cost per DALY averted in this population? Brief methods: Calculate the incremental costeffectiveness ratio (ICER), with net costs (program costs adjusted for changes in future HIV medical care costs) in the numerator, and DALYs averted in the denominator. 29
    30. 30. Introducing decision trees • Graphically portrays the decision & its effects • Three major components: – The action options (the decision) under consideration. – The probabilistic mix of consequences for each option. – The value of health and cost outcomes for each consequence. • Calculates the “expected value” for health and cost outcomes for each option, as the weighted mean for the mix of consequences. 30
    31. 31. A Basic Decision Tree Voluntary adult male circumcision for HIV prevention in rural Kenya HIV infection 0.4 No camp No HIV infec. 0.6 Mobile circ. camp? # men 100 HIV infection 0.2 MC Camp No HIV infec. 0.8 31
    32. 32. Adding Health Outcomes New HIV infections Per person DALYs due to new HIV infections 7 HIV infection 0.4 40 280 No HIV infec. 0.6 0 0 HIV infection 0.2 20 140 No HIV infec. 0.8 0 0 No camp Mobile circ. camp? # men 100 MC Camp Infections averted DALYs averted 20 140 32
    33. 33. Adding Intervention Costs New HIV infections Per person HIV infection 0.4 40 DALYs due to new HIV infections Cost of MC Camp 7 $100 280 $0 No camp No camp? No costs! No HIV infec. 0.6 0 $0 HIV infection 0.2 Mobile circ. camp? # men 100 0 20 140 $2,000 No HIV infec. 0.8 0 0 $8,000 MC Camp Infections averted DALYs averted 20 140 Camp cost $10,000 33
    34. 34. Adding Medical Care Costs New HIV infections Per person DALYs due Cost of MC to new HIV Camp infections Cost of HIV medical care (if new HIV infection) 7 $100 $6,000 $240,000 HIV infection 0.4 40 280 $0 No HIV infec. 0.6 0 0 $0 HIV infection 0.2 20 140 $2,000 No HIV infec. 0.8 0 0 $8,000 No camp Mobile circ. camp? # men 100 $120,000 MC Camp Infections averted DALYs averted 20 140 Camp cost Med. Costs averted $10,000 $120,000 34
    35. 35. And Finally – Results! New HIV infections Per person DALYs due Cost of MC to new HIV Camp infections Cost of HIV medical care (if new HIV infection) 7 $100 $6,000 $240,000 Total cost HIV infection 0.4 40 280 $0 No HIV infec. 0.6 0 0 $0 HIV infection 0.2 20 140 $2,000 No HIV infec. 0.8 0 0 $8,000 $240,000 No camp Mobile circ. camp? # men 100 $0 $240,000 $120,000 $122,000 MC Camp Infections averted DALYs averted 20 140 ICER ($/DALY averted) $8,000 $130,000 Camp cost Med. Costs averted Net costs $10,000 $120,000 ($110,000) Dominant 35
    36. 36. CEA Example B – Specific Aims Cost-effectiveness of adherence counseling for HIV anti-retroviral therapy (ART) in a primary care clinic in rural India, as part of an RCT • Specific Aim 1: Measure the cost in this primary care setting of adherence counseling per client receiving the service and per patient-year of ART. • Specific Aim 2: Estimate the impact of adherence counseling on HIV disease progression and disabilityadjusted life years (DALYs) over three and ten years. • Specific Aim 3: Calculate the cost per added individual with viral suppression and the cost per DALY averted. 36
    37. 37. CEA Example B – Specific Aim 1 Cost-effectiveness of adherence counseling for HIV anti-retroviral therapy (ART) in a primary care clinic in rural India, as part of an RCT • Specific Aim 1: Measure the cost in this primary care setting of adherence counseling per client receiving the service and per patient-year of ART. Brief methods: Review program financial and service records for a 12 month period, in order to quantify adherence counseling costs (resources used and associated costs) and client-years of ART. Use time and motion methods to separate staff effort dedicated to adherence counseling from other activities. 37
    38. 38. CEA Example B – Specific Aim 2 Cost-effectiveness of adherence counseling for HIV anti-retroviral therapy (ART) in a primary care clinic in rural India, as part of an RCT • Specific Aim 2: Estimate the impact of adherence counseling on HIV disease progression and disabilityadjusted life years (DALYs) over three and ten years. Brief methods: Build a decision analysis to portray HIV disease progression on ART as a function of viral suppression, and associated DALYs due to premature mortality and morbidity. Set model values for three years from RCT results, and project to ten years using disease state modeling. 38
    39. 39. CEA Example B – Specific Aim 3 Cost-effectiveness of adherence counseling for HIV anti-retroviral therapy (ART) in a primary care clinic in rural India, as part of an RCT • Specific Aim 3: Calculate the cost per added individual with viral suppression and the cost per DALY averted. Brief methods: Compare program costs to RCT measures of rate of viral suppression. Calculate the ICER ($ per DALY averted) with net costs (adherence counseling costs adjusted for changes in ART costs) in the numerator, and DALYs averted in the denominator. 39
    40. 40. Cost-effectiveness of adherence counseling for ART, primary care clinic in rural India, in RCT Simplified tree Health outcomes Deaths on ART (3 years) Per person Death 0.2 DALYs (death; alive) 10 4 Health outcomes Cost of Cost of HIV Adherence medical care Total cost Counseling (death; alive) $30 $1,200 $7,000 0.2 2 $240 $240 0.8 0.8 3.2 5.2 $5,600 $5,600 $5,840 Death 0.15 0.15 1.5 $5 $180 $185 Alive 0.85 0.85 3.4 4.9 $26 $5,950 $5,976 $6,160 DALYs averted 0.3 Cost $320 No Alive Adherence counseling? # patients 1 Yes Comparing ICER ($/DALY averted $1,067 40
    41. 41. What cost-effectiveness research question are you interested in? • What is: – the intervention? – the comparator? • What outcome measures are appropriate? • How will you evaluate intervention benefits? • How will you measure program costs? • Will you adjust for changes in direct medical costs resulting from the intervention? • Can you sketch a tree that portrays the consequences of the intervention and its comparator? 41

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