Public Health 2 Exam 2
What do we use conditional probabilities for?
"downstream" nodes - p(A)=0.10 prob. you're asleep - p(B)=0.25 prob. you understand DA - p(B|A)= prob. you understand DA given that you are asleep 1.0? 0.0?
What is the multi-attribute health index (HUI, QWB, EuroQOL) method for assessing utility?
- A multi-attribute health status instrument with preference weighted items. - The sum of the individual weighted items is then scaled to reveal a result between 0 and 1.
What are some PPACA quality rating system (QRS) measures?
- Antidepressant medication management - appropriate treatment for URI - childhood immunizations - comprehensive diabetes care (A1C and nephrology) - Controlling high BP
Look at the examples at the end of the ppt
- BP - Osteoporosis - statin adherence - ED visits
What are some policy issues related to silo thinking?
- Budgets as silos - E.g. pharmacy vs. medical insurance budgets - Identity: every expenditure is somebody's possible income
What is involved in Step 2. Draw out the tree Decision Tree Conventions?
- Build left to right - Nodes - decision nodes (squares) - chance or probability nodes (circles) - Event placed above "branch" - Probability of event placed below "branch"
What is involved in Step 4. Analyze the tree?
- Calculate expected value of each strategy - Also referred to as "rolling back" or taking the average of the tree - Start at terminal node and multiply probabilities as you trace tree to origin to get probability of outcome - Sum weighted outcomes for each strategy
What is involved in standard gamble?
- Calculating utility for SG means determine the preference for probability of perfect health (P) and death (1-P) - Utility = P - SG is a true measure of utility, accounts for preference and uncertainty - Affected by risk attitude (risk seeking vs risk averse)
What is the general approach for sensitivity analysis?
- Change model input - Recalculate ICER - Compare results from base-case and sensitivity analysis
What are net benefits?
- Combines information on costs, outcomes, and WTP - Net Monetary Benefits - Positive number indicates technology is cost-effective - Overcomes some limitations of analyzing ratios, however it subject to a WTP threshold which must be known or estimate net benefit across multiple WTP
How do you calculate ICER?
- Compare new treatment to old treatment (old treatment could be standard of care, no treatment, etc.) - Calculate change in cost (CN-CO) - Calculate change in effect (EN-EO) - Divide change in cost by change in effect (CN-CO)/(EN-EO)
What is involved in Step 3. Gather the data?
- Conduct systematic search where appropriate - Can use RCT's, meta-analysis, expert opinion, etc. - Use best estimate for "base-case" analysis - Use 95% CI's or ranges for sensitivity analysis
What are some inputs to vary ?
- Cost - Outcomes - Life Years - Utilities - Probabilities - Risks - Discount Rate
What are forms of pharmacoeconomic evaluations?
- Cost-consequence analysis (CCA) - Cost-effectiveness analysis (CEA) - Cost-utility analysis (CUA) - Cost-benefit analysis (CBA)
What does a probabilistic sensitivity analysis output entail?
- Cost-effectiveness cloud (scatterplot on cost-effectiveness plane) - Cost-effectiveness acceptability curve - Net benefits
Learning objectives:
- Describe what pharmacoeconomics can and cannot accomplish - Explain components in framing and displaying cost-effectiveness evidence - Examine policy implications of pharmacoeconomics - Describe the elements in a cost-effectiveness analysis and how to critique a CEA - Seven steps for conducting a CEA - Demonstrate how steps are met with Campbell et al article (Xolair® CEA) - "Quality" Score for the critique of a CEA - Exercise on scoring Kansal et al article using Excel® QHES scoring spreadsheet
What are some problems in application?
- Different methods produce different results. - Problems with numeracy - The validity of standard utility assessments (SG and TTO) is related to the subjects facility with numbers. - Comparability of studies using different health states, different judges, and different methods. - Especially for QALY league table comparisons. - A QALY is a QALY is a QALY
Objectives
- Differentiate between fee-for-service and value-based healthcare - Explore the meaning and measurement of healthcare quality - Describe different structures for value-based healthcare models AND how each influences provider and payer behavior - Identify how to apply a pharmacist's unique skills to improve quality of care for patients with osteoporosis
What are limitations of decision analysis?
- Difficult to model long-term time horizons - Framework is not very dynamic (cannot easily model progression of disease or transitions from one health state to another) - many interventions (particularly pharmaceuticals) target chronic diseases that progress over decades - long-term costs and outcomes are important for CEA and HTA - long-term follow-up data on cost and outcomes often are lacking
What must be true for a node on a decision tree?
- Each event at a node must be mutually exclusive and exhaustive - Thus, the sum of the event probabilities at a node must be 1.0
What are strengths of a one-way sensitivity analysis?
- Easy to conduct - Understand which parameters have the most impact/influence - Can provide targeted recommendations based on one-way results
What are the five domains of quality targets for HEDIS?
- Effectiveness of care - access to care - experience of care - utilization - plan descriptive information
What is the IHI Triple Aim?
- Experience of care - Health of a population - Per capita cost
What are some important aspects of a transparent analysis?
- Figure 1 - structure (conceptual framework) of the analysis/model - Table 1 - inputs, uncertainty and sources - key assumptions of the analysis / model (either in table for text form)
What are some applications of QALY?
- Health utility estimation for type 1 diabetes patients across HbA1c at the Barbara Davis Center for Diabetes - Estimation of quality-adjusted life years for the average multiple sclerosis patient
What are BIM applications?
- In particular, a BIM predicts how a change in the mix of drugs and other therapies used to treat a particular health condition will impact the trajectory of spending on that condition - Budget planning - Computing the impact of health technology changes on premiums in health insurance schemes - Formulary approval or reimbursement submissions
What are some general conclusions?
- Increasing demand for economic evaluation - Payers focus on value for money - Economics helps but it does not make decisions - Emerging role of pragmatic trials with CE - Patient-centered outcomes; QOL, utility - Need for transparency of studies
Who does decision analyses?
- Making real-world decisions often involves assessing the probability and value of multiple outcomes - It is difficult to evaluate complex decisions - Decision analysis allows for the incorporation of data from multiple sources, makes assumptions explicit, and quantifies the decision parameters
What are some other methods for cost effectiveness?
- Markov Model (Population-level health state transition model) - good for chronic diseases - Discrete Event Simulation (Patient-level disease simulation model) - best for complex diseases where there is heterogeneity in the study population that drives varying risk of consequences. Often, patient-level data and analyses are needed to build a discrete event simulation.
What is involved in CEA step 4: select, identify, and measure costs and clinical inputs?
- Measuring and valuing costs and clinical inputs - inflation (costs), discounting depending on time horizon
What are the two tracks of What is the medicare access and CHIP reauthorization act of 2015?
- Merit based insentive payment system (MIPS) - advanved alternative payment models (AAPMS)
What is a probabilistic sensitivity analysis?
- Model inputs are specified as a distribution and varied within distribution - Most often this involves multiple input variation at the same time
What is a cost-benefit analysis (CBA)?
- Monetary values (willingness to pay) - Contingent valuation - Conjoint analysis
What bounds to input ranges do we use for one-way sensitivity analyses?
- Most often use lower and upper bound of input range - Relative Risk: 0.88 (0.79, 0.95) - Base-case uses 0.88 to get the base-case ICER - Keeping all other inputs the same, change relative risk to 0.79 (lower bound) - Record ICER - Keeping all other inputs the same, change relative risk to 0.95 (upper bound) Record ICER
What are quality adjusted life years (QALYs)?
- Most therapies have multiple heath consequences - Trade-offs between survival and quality of life (e.g., chemotherapy) - Trade-offs between different aspects of health (e.g., depression and dry mouth from drug therapy) - Policy makers need to compare across diseases - QALYs and cost-utility analysis
What is a cost-utility analysis (CUA)?
- Multiple outcomes combined into weighted index (QALYs)
What is a cost-consequence analysis (CCA)?
- Multiple outcomes in natural units ("consumer report")
What do each quadrant of the cost effectiveness plane mean?
- NE Quadrant: More costly, More effective when is this cost-effective? - NW Quadrant: More costly, Less effective when is this cost-effective? - SW Quadrant: Less costly, Less effective when is this cost-effective? - SE Quadrant: Less cost, More effective when is this cost-effective?
Why is the visual analog scale not a true measure of utility?
- Not preference-based - Not compared to death or alternative health states - No cost or consequence for marking near 'zero' - No time horizon specified... Do you have blindness now or later?
What is the Standard Gamble method for assessing utility?
- Offers a choice between two alternative health states: 1) living in health state A with certainty or 2) taking a gamble on treatment for which the outcome is uncertain - health state B. - The respondent is described health state A with intermediate value between well and dead. Then, the respondent is told that treatment will lead to perfect health with a probability of P or immediate death with a probability of 1-P. The value of P is varied until the respondent is indifferent between A and B. - Includes trade-off and uncertainty.
What are ways to assess uncertainty in model inputs?
- One-way sensitivity analysis - Probabilistic sensitivity analysis (cost-effectiveness acceptability curve or value of information analysis)
What are limitations of a one-way sensitivity analysis?
- Only varies one parameter at a time - Assumes that uncertainty exists in only one parameter - This is never really the case - ICER is based off of multiple parameters, each with variation - Because of this, one-way sensitivity analyses underestimate uncertainty
What are the sources for healthcare spending?
- Out-of-pocket - private spending - public spending
What is involved in Step 5. Run Sensitivity Analyses?
- Perform 1-way sensitivity analyses on all inputs (parameters) to debug tree - Vary probabilities from 0 to 1; response of model to changes should be logical - Set all costs/outcomes to zero; strategies should have same expected value - Perform probabilistic sensitivity analysis
What is pharmacoeconomics definition?
- Pharmacoeconomics is the scientific discipline that assesses the overall value of pharmaceutical health care products, services, and programs. Of necessity, it addresses the clinical, economic, and humanistic aspects of health care interventions in the prevention, diagnosis, treatment, and management of disease. Pharmacoeconomics thus provides information critical to the optimal allocation of health care resources. The field encompasses experts of health economics, risk analysis, technology assessment, clinical evaluation, epidemiology, decision sciences, and health services research (International Society for Pharmacoeconomics and Outcomes Research Book of Terms).
What are cost-effectiveness clouds?
- Plots ICER from each iteration on the cost-effectiveness plane - Observe what quadrants the resultant ICERs reside - Often graph WTP line to visualize portion of cloud under line - Could plot multiple WTP lines
What is a cost-effectiveness acceptability curve (CEAC)?
- Plots percentage of iterations that favor each strategy for a range of WTPs - Y axis: probability of being cost-effective - X axis: WTP
What is involved in framing the cost-effectiveness question?
- Population - Comparator(s) - Viewpoint (Hospital, Health Care System, Society) - Time horizon (long enough to capture main costs and effects)
What is prefernce-weighted measures in economic evaluation?
- Provides a single index number constrained between the values of 0 (dead) and 1 (perfect health) - Are usually generic but may be disease specific - Are preference-weighted using weights derived from community or patient studies.
What are some existing preference-weighted scales in economic evaluation?
- Quality of Well Being Scale (QWB) - Health Utilities Index (Mark I, II, III) - EQ-5D - SF-6D
What are common methods for assessing utility?
- Rating scales - Magnitude estimation - Standard gamble - Time-trade-off - Multi-attribute index (HUI, QWB, EuroQol)
What is the incremental cost-effectiveness ratio (ICER)?
- Ratio of difference in cost to difference in effectiveness: ICER = ∆C / ∆E = (CA - CB) / (EA - EB)
What is the medicare access and CHIP reauthorization act of 2015?
- Repeals the medicare sustainable growth (SGR) formula - replaces pure FFS with new payment system with two tracks
What is the rationale behind cost effective analysis?
- Scarcity of resources - Need to make choices: opportunity cost - Decisions need to be based on comparisons of costs and benefits - Efficiency is not the same as cost cutting
What is outcome assessment in terms of mortality?
- Scored 0 if dead and 1 if alive. - Allows for very simple comparison of outcome across different disease states. - The difficulty is that everyone who remains alive is given the same score (1).
What are some policy issues related to "leakage"?
- Should policies restrict usage where CE is most attractive? - Cost effectiveness of a drug depends on when, how and in whom it is used - General reimbursement = usage can be non-specific and "leakage" occurs - Restriction policies: prior authorization etc.
What is a cost-effectiveness analysis (CEA)?
- Single outcome - Intermediate: blood pressure - Final: life years gained
What are input and data sources for BIM?
- Size and characteristics of affected population - Current intervention mix without the new intervention - Costs of current intervention mix - New intervention mix with the new intervention - Cost of the new intervention mix - Use and cost of other health condition- and treatment-related health care services
What is time trade-off (TTO)?
- Subject is offered a choice of living for a variable amount of time in perfect health or a fixed amount of time in an alternative health state (disease with given treatments) that is less desirable. - A trade-off exercise is undertaken to arrive at an indifference point between the suboptimal health state with a fixed time period (1 year) and a variable time period in optimal health. - For example, a person with ESRD undergoing dialysis may rate 1-year of dialysis as equivalent to 0.5 years of perfect health. - Includes trade-off, but no uncertainty.
How do you calculate utility from TTO?
- Take normal life expectancy (LE) in current state - Determine the years of TTO for perfect health (X) - Utility = X/LE - The more years of life you are willing to give up in a current state for perfect health, the worse your health state is. - More challenging than VAS. - Still no risk or uncertainty involved; not a true utility.
What is the conceptual framework to QALY?
- The concept of the QALY dates back to 1970 (Fanshel and Bush). - The approaches vary, yet each sets one year of optimal or healthy life equal to the value 1.0 and death equal to 0.0. - Some (Patrick, et al.) have argued that there are states of health worse than death, in which case one would have to re-scale the measurement tool. - The disagreement with this concept is not over its appeal as an outcome measure, but over how the weights between 0 and 1 are derived.
What are some policy issues related to cost effectiveness vs budget impact and affordability?
- Two drugs can have the same incremental cost-effectiveness but very different budget impact - Payers consider affordability as well as efficiency - Some jurisdictions set agreed forecast usage with drug manufacturer
What is parameter uncertainty?
- Uncertainty in estimation of parameter of interest - There is uncertainty and variation in model inputs - Base-case/deterministic analysis only uses a point estimate of an input
What are inputs for a one-way sensitivity analysis?
- Use 95% Confidence Interval - Vary parameter by arbitrary range (± 20%, 40%) - Models sensitivity, doesn't really model uncertainty - Expert opinion
What are preference measurement strategies?
- Use validated instrument with existing preference weights. - Directly elicit preference weights, if no validated instrument is available. - Use weights from published literature or registries. - Trace original source and method - Use weights derived from experts.
What is the concept of utility?
- Utility assessment is the acknowledged method for eliciting preference weights for QALY calculations. - Depends on context
What is a probabilistic sensitivity analysis more specifically?
- Vary multiple parameters at once - Each variable comes from a distribution - Run model many times (1,000x, 10,000x, etc.) - Each iteration plucks a value from the distribution for EACH input - Uses that value as the model input for that iteration
One-way sensitivity analysis method:
- Vary one input at a time, keeping all other inputs the same - Record output - Compare output to base-case results
What is involved in CEA step 6: sensitivity analysis?
- Vary parameters to see how sensitive your conclusion is to your assumptions - Robust results don't change qualitatively as you vary key parameters - Figure 2 - one-way sensitivity analysis (tornado diagram)
What is involved in Step 1. Identify and Bound the Problem?
- What is the decision problem; what is the research question? - What are the potential alternative actions? - What are the events that follow the decision?
Some questions to ponder:
- Why is there a $$$ disparity with such poor outcomes? - Why is healthcare so expensive? - Why is US healthcare quality so low?
What is the role of a community pharmacist in value based care in terms of emerging models?
- accountable care organizations - other value based models
What does the breakdown of MIPS score look like?
- cost 15% - improvement activities 15% - promoting interoperability 25% - quality 45%
How complex should a decision tree be?
- factors that impact cost-benefit must be included - But a model that is unnecessarily complex may be ineffective for influencing decisions - Model structure is usually data driven - Model building is an iterative process
What is the difference in cost, including the rebate of Biotechumab vs. generic per patient per year?
-$500
Objectives:
-Describe the concept of the quality-adjusted life year (QALY) and utility -Explain methods for assessing utility -Debate application challenges
What is involved in CEA step 5: report results?
-Transparency, replicability (to allow further studies to either refute or support the findings) - Table 2 - disaggregate results on costs and consequences as well as incremental cost-effectiveness ratio (ICER)
What is the prevalence rate of colon-cancer in this organization?
0.07%
How many decision nodes are there on the tree above?
1
What are the HEDIS star ratings?
1 - poor 2 - below avg 3 - avg 4 - above avg 5 - excellent
What are the seven steps for CEA?
1. Define the problem 2. Identify treatment alternatives and cost-effectiveness outcomes 3. Select a study design 4. Select, identify, and measure costs and clinical inputs 5. Report results 6. Sensitivity analysis 7. Limitations
Objectives:
1. Discuss steps in conducting a decision analysis for estimating cost effectiveness 2. Describe limitations of a decision tree approach and other alternative modeling methods 3. Comprehend budget impact models: definition, components, and applications 4. Analyze an applied cost-effectiveness question using decision tree and budget impact approaches (hear, see, do).
What is involved in the quality improvement process?
1. Plan - background and research 2. Do - pilot 3. Study - evaluate process or outcomes 4. Act - revise process, implement process
Objectives:
1. Review cost-effectiveness calculations 2. State the purpose of conducting a sensitivity analysis 3. Summarize the various methods of conducting a sensitivity analysis 4. Interpret output from sensitivity analyses 5. Demonstrate the effect of changing a parameter on the deterministic results
What were the three primary goals of the patient protection and affordable care act of 2010?
1. increase access to affordable health insurance 2. expand medicaid coverage 3. support innovation
What is the treated population (N) of end-stage colon cancer?
175
How many chance nodes are there on the tree above?
4
About how many patients will switch from generic treatment to Biotechumab?
53
How many terminal nodes are there on the tree above?
6
Based on the table above, how many QALYs would each treatment yield (new vs SOC)?
9 years * 0.9 = 8.1 12 years * 0.75 = 9
What is the probability of death without side effects for Drug A?
=0.5*0.25 = 0.125
What is the definition of decision analysis (DA)?
A systematic approach to decision-making under uncertainty that permits: (1) a structure to the decision, (2) consequences for each alternative, and (3) assessment of degrees of uncertainty.
What does a health system need to succeed in value-based reimbursement programs?
A. Leadership/culture that prioritizes the triple aim B. Sophisticated data analytics capability C. Multidisciplinary care management teams D. All of the above
What could a pharmacist measure in HEDIS?
A. Medication management for people with asthma B. Controlling high blood pressure C. Statin therapy for patients with cardiovascular disease D. Osteoporosis management in women who had a fracture E. Antidepressant medication management F. Metabolic monitoring for children and adolescents on antipsychotics
A new drug is evaluated against a usual care alternative and is shown to have an ICER of 35,000/QALY from the payer perspective. For a health plan, the number of patients who could switch to the new drug will cost the plan an additional $0.12 per member per month. Will a health plan that uses both efficiency and affordability evidence adopt the new drug onto its formulary?
A.Unknown, the WTP per QALY and affordability threshold are unknown to the payer.
What are some legislative drivers of value-based reimbursement?
ACA (2010) MACRA (2015)
What is outcomes assessment in terms of preference (utility)?
Assessment allows the quantification of different levels of wellness on a continuum anchored by death (0) and perfect or optimum health (1).
This type of economic analysis compares BOTH the costs and benefits in dollar terms.
Cost benefit
This type of economic analysis compares the costs and benefits in dollar terms:
Cost benefit
What are BIM output (outcomes)?
Cost per member per month (rule of thumb is < $0.05 is relatively affordable).
What is the output of budget impact model?
Cost per strategy
What are payoffs?
Costs and health outcomes assigned to different 'heath states' or disease statuses or prognoses.
DECISION ANALYSIS FOR CEA AND BUDGET IMPACT PPT
DECISION ANALYSIS FOR CEA AND BUDGET IMPACT PPT
Which model best describes how a pharmacist gets paid?
Decreased ED visits and hospitalizations
What will happen to the third party payer budget if they include Biotechumab on the formulary (include the rebate in your calculation)?
Decreased budget impact
What are the pharmacy quality alliance (PQA) quality measures for community pharmacies?
Developed, tested, and endorsed: 1. proportion of days covered (PDC) for renin angiotensin system antagonists 2. PDC statins 3. PDC antiretroviral medications
Drug A costs $50,000 and has an effectiveness of 0.85 QALYs. Drug B costs $48,000 and has an effectiveness of 0.89 QALYs. What is the ICER?
Drug B dominates Drug A
EXAM 2 PREPARATION PPT
EXAM 2 PREPARATION PPT
What is the economic definition of utility?
Economists define utility as the level of "satisfaction" gained with goods and services purchased under certainty. e.g. Product attributes are known. Utility is quantified using cardinal numbers.
Cost-effectiveness addresses the questions related to ____ whereas budget impact addresses questions related to ____?
Efficacy Affordability
True or false: decision trees should not have symmetry.
False - decision trees should have symmetry where possible.
From Dr. Billups lecture, what two extremes of health care reimbursement models did she compare and contrast?
Fee for service vs value-based healthcare.
What is the budget impact model (BIM)?
Goal: Estimates the financial consequences of adoption and diffusion of a new health-care intervention within a specific health-care setting or system context given inevitable resource constraints - Estimates affordability (not efficiency as in cost-effectiveness)
What are the quality measures and how are they applied to practice?
HEDIS for medicare advantage or commercial health plans.
What is the health economist definition of utility?
Health economists define health utility differently as an expression of preference for a health state under conditions of uncertainty. e.g. Risks and benefits are unknown statically and temporally
What is HEDIS?
Healthcare Effectiveness Data and Information Set
Healthcare spending as %GDP vs life expectancy in the US:
Healthcare spending is highest in the US (16.9%) and life expectancy is low compared to other industrialized countries (78.6 years)
What are some PQA pharmacy measurement concepts?
Hemoglobin A1c Reporting, Improvement, Control -Blood Pressure Reporting, Improvement, Control -Flu vaccine Screening, Administration - Antidepressant Medication Management -Asthma Controller Therapy -Primary Medication Nonadherence -Abandonment Rate - Early Persistence to Oral Oncolytics - Patient Experience with Pharmacy Services -Pharmacy-administered Disease Assessment (e.g. RAPID3 for rheumatoid arthritis) -Screening for Social Determinants of Health
What is the outcome of cost-utility model
ICER = Δcost/ΔQALYs
What is the outcome of cost-effectiveness model?
ICER = Δcost/Δhealth effect
INTRODUCTION TO PHARMACOECONOMICS AND COST-EFFECTICENESS ANALYSIS PPT
INTRODUCTION TO PHARMACOECONOMICS AND COST-EFFECTICENESS ANALYSIS PPT
What are the input values and output of base-case analysis?
Input - mean/ point estimate Output - ICER
What are the input values and output of sensitivity analysis?
Input - variation around the mean Output - variation around ICER
What are probabilities?
Likelihood of event taking place in future - Probability theory has many definitions - joint, conditional, independence, mutually exclusive and exhaustive...
From the question above, this treatment is said to be good value for money if the ICER is _____ than the willingness to pay threshold.
Lower
What is involved in CEA step 2: identify treatment alternatives and cost-effectiveness outcomes?
Make sure you include relevant alternatives. - don't leave out major comparisons
What is a one-way sensitivity analysis?
Model input is specified as a point estimate and varied manually
What are capitation quality incentives?
National committee for quality assurance (NCQA) has quality standards for accreditation (required by government payers like CMS, CHP and some private employers). - Medicare has $ incentives for high HEDIS scores.
What is the output for cost benefit model?
Net social benefit = incremental benefit (cost) - incremental costs
Drug A costs $10,000 and has an effectiveness of 0.90 QALYs. Drug B costs $20,000 and has an effectiveness of 0.95 QALYs. Is drug B cost-effective at a willingness-to-pay threshold of $100,000/QALY?
No, Drug B's ICER is greater than the willingness-to-pay threshold
PREFERENCE ASSESSMENT PPT
PREFERENCE ASSESSMENT PPT
What is the role of a community pharmacist in value based care in terms of barriers?
Payment models - IT / data sharing limitations - Pharmacist Training in QI, quality environment - Evidence of ROI for community pharmacy practitioners
From Dr. Billups lecture, what three components are included in the triple aim of health?
Per capita cost Health of a population Experience of care
What is involved in CEA step 1: defining the problem?
Perspectives! - determines which costs to include and to whom - framing the cost-effectiveness question
Compared to standard of care (SOC) for a certain disease state, if a new treatment strategy was evaluated and found to be more costly and to be more effective, then the incremental cost-effectiveness ratio is what?
Positive
SENSITIVITY ANALYSIS USING DECISION TREES PPT
SENSITIVITY ANALYSIS USING DECISION TREES PPT
What is a solution to the limitations of a one-way sensitivity analysis?
SOLUTION: Probabilistic Sensitivity Analysis
What is the main reason the standard gamble is considered the best measure of health utility based on economic theory?
Standard gamble incorporates tradeoff and uncertainty.
What is involved in CEA step 7: limitations?
Study limitations should be noted and discussed. - Results should be compared to other estimates in the literature. - Analysis should shy away from suggesting that a particular product is "cost-effective". This determination should be reserved for decision makers.
What is the visual analog scale?
The VAS is a scale that asks you to rate exactly how you feel, typically on a 100-point scale (the feeling thermometer)
What does sensitivity analyses evaluate?
The effect of uncertainty and variation in inputs on model outputs
When do we use a decision analysis?
There should be some uncertainty about the appropriate clinical strategy - Clinical trial may not include all outcomes - Different levels of risk have not been evaluated - The interventions to be compared should have tradeoffs - Effectiveness vs. cost and benefit vs risk
What is a one-way sensitivity analysis output and what does it tell you?
Tornado diagram. - Tells you which input has the greatest impact on output - Width of bar represents impact on model - Greatest width=greatest impact - Axis of tornado diagram is often the base-case ICER - Can see if results cross WTP threshold - Order bars from most influence to least influence (tornado shape)
What is involved in CEA step 3: select a study design?
Trial or other data source vs simulation/ models - should be driven based on the best available evidence
True or false: if sensitivity analysis ICER is very different from base-case ICER, model is sensitive to the value of that parameter
True
True or false: the NW quadrant of the cost-effectiveness plane suggests the new proposed treatment is less effective and more costly than the existing treatment (SOC).
True
True or false: the SE quadrant of the cost-effectiveness plane suggests a new treatment vs SOC is more effective and less costly.
True
Based on the table above, what is the incremental cost-effectiveness ratio or value of the new treatment?
Usual care dominates new treatment because lower effectiveness and higher cost.
VALUE-BASED HEALTHCARE PPT
VALUE-BASED HEALTHCARE PPT
What are expected values?
Weighted average of a random variable (rv) where weights correspond to probabilities (discrete rv) or densities (continuous rv). The integral of rv with respect to its probability measure.
Which of the following payment models is not an example of value-based care?
a. performance b. risk c. fee for service d. capitated
Which of the following payment models is NOT an example of value-based care?
a. performance-based b. risk-based c. fee for service d. capitated
In a typical fee-for-service model, which of the following services will get reimbursed?
a. physician assessing a pt with arthritis b. physician calling a pt to discuss lipid lab results and start statin therapy c. nurse calling a patient to discuss lipid lab results and start statin therapy d. physician discussing lipid lab results and starting statin therapy at a clinic visit e. pharmacist reviewing a patient's diabetes regimen at a clinic visit
Summary:
➧ All inputs have uncertainty ➧ Base-case analysis does not capture variation/uncertainty in value ➧ Sensitivity analyses test how uncertainty affects results by varying inputs ➧ One-Way Sensitivity Analyses - Present results through a decision tree - Understand influential inputs ➧ Probabilistic Sensitivity Analyses - Present results through scatterplot or CEAC - Evaluates combination of uncertainty in inputs
What are the steps of a probabilistic sensitivity analysis?
➧ Assign distribution to a variable - Define distribution shape (normal, log normal, beta, etc.) ➧ Create the distribution - Define distribution parameters (mean, variance, alpha, beta, etc.) ➧ Repeat for all variables with uncertainty ➧ Determine number of iterations (Monte Carlo simulations) ➧ Run model for the number of iterations - Each run will pull a value from the distribution for each parameter
