1,000 word essay aligned with the Drummond checklist critiquing the quality of the assigned article

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week9economic.docx

Lack of Transparency and Quality Barriers to Modeling Utilization

Modeling Challenges

· Does not always lead to choices that maximize public health and limited resources

· Is complicated and not as easily understood as traditional randomized clinical trials

· Represents a relatively new field

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Questions for the

Decision-Makers

· Are the results helpful?

· Are the methods appropriate?

· Are the results valid?

· Do valid results apply to my decision context?

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Transparency

· Indicates compliance with established quality standards

· Refers to clear description of the model structure, equations, parameters, and assumptions

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Transparent Documentation

· Lay summary, accessible to any interested reader

· Model type and intended application; funding sources; model structure; model inputs, outputs, and components; and validation methods, results, and limitations

· Detailed technical document, allowing expert evaluation and potential recreation

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While meeting technical and lay reporting guidelines does not ensure that the model is correct, validation is not possible without a clear understanding of the model.

Defining a Study Question, Perspective, and Scope

What's a Good Question?

· Is well defined and in answerable form

· Clearly identifies the alternatives being compared

· Identifies the perspective from which the comparison is made

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Examples of Bad Questions when alternative is specified

· Is an active PE policy intervention worth it?

· Will a smoking-cessation intervention do any good?

· How much does it cost to run our syringe-exchange program?

· What are the costs and outcomes of the school wellness policy?

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Quality Checklist

Quality Dimension

Good Practice Attributes

Critical Appraisal Questions

S1: Statement of decision problem/objective

• A clearly stated decision problem

• Is the decision problem clearly stated?

• A defined evaluation and model objective

• Is the evaluation and model objective specified and consistent with the decision problem?

• A clearly stated primary decision-maker

• Is the primary decision-maker specified?

S1: Statement of scope/perspective

• A clearly stated model perspective (relevant

costs and consequences) and model inputs consistent with the stated perspective and overall model objective

• Is the model perspective stated clearly? Are the model inputs consistent with the stated perspective?

• A specified and justified decision model scope

• Is the model scope stated and justified?

• Model outcomes that reflect its perspective and scope and are consistent with the objective

• Are the model outcomes consistent with its perspective, scope, and overall objective?

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A Good Question

From the perspective of (a) both the Ministry of Health and the Ministry of Community and Social Services budgets and (b) patients incurring out-of-pocket costs, is a chronic home care program preferable to the existing program of institutionalized, extended care in designated wards of general hospitals?

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Study Perspective

· May be a deciding factor of comparative cost-effectiveness

· Should justify any departure from societal perspective and explain any expected impacts on results

Description of Alternatives and Effectiveness Estimates

Comprehensive Description

· Should be provided for each competing alternative

· Who did what to whom, where, and how often

· Helps readers judge relevance to a given setting

· Allows readers to detect cost or consequence omissions

· Provides enough information for program duplication

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Proper Inclusion

· Represents the full range of potential alternatives

· Covers all feasible and practical options, regardless of data availability

· Includes any extendedly dominated options

· Explores the appropriateness of a "do nothing" option

· Compares to the current practice if only one comparison is made

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Effectiveness Estimates

· Are valid effectiveness estimates included for each alternative?

· Are the estimates convincing?

· Is the evidence produced by a single study?

· Does it represent the field's broader evidence?

· Did the authors justify use of a single source?

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Systematic Review

· Helps demonstrate the evaluation's effectiveness

· Thoroughly covers underlying methods, even if cited from previous works

· Evaluates causal inference from quasi-experimental or observational data

· Avoids reliance on randomized controlled trial data for effect size

Measurement and Valuation of Costs and Consequences

Phases of Costing

· Studies often conduct identification, measurement, and valuation simultaneously.

· Quality evaluation considers each step separately.

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Identification

· Was the full range of costs and consequences included?

· Could an expert assess the completeness?

· Were all the relevant perspectives covered?

· Were both capital and operating costs included?

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Measurement

· Were the resource utilization sources described and justified?

· Were any identified items omitted?

· Were there any special circumstances that complicated measurement?

· E.g., overhead costs paid from shared resources

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Valuation

· Were sources identified for all values?

· Were approximations made for any absent market values (as for volunteer labor)?

· Were consequences valued appropriately for the question (e.g., conversion of health effects to monetary value for cost-benefit analyses)?

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Valuation (cont.)

· Were measurement-strategy-related variations in health state valuation described and justified?

· State-to-preference mapping method

· Preference elicitation details

· Were costs and consequences discounted to their present value? Were the discount rates justified?

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Incremental Analyses

· Were the comparisons properly chosen?

· Were both strongly dominated and extendedly dominated alternatives included?

· Were the calculations for the final, best incremental cost-effectiveness ratio well documented?

Description of Uncertainty Analyses

Patient-Level Costs

and Consequences

· Were appropriate statistical analyses performed?

· Were the proper distributions used?

· How were missing data addressed?

· Were alternative statistical techniques used to accurately model the incremental cost-effectiveness ratio uncertainty from trial data?

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Parameters

· Were all of the uncertain parameters identified?

· Were parameters with no assumed uncertainty identified?

· Was any lack of uncertainty justified (e.g., known with absolute certainty)?

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Specifying Uncertainty

· If an arbitrary range of plausible values was used for important parameters, was empirical justification provided for it and the distribution shape?

· Were easy-to-fit distributions (e.g., triangular) with limited statistical justification used?

· Was unavoidable lack of uncertainty evidence for any important variable clear in results discussion?

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Sensitivity Analyses

· Was justification made for any departure from a probabilistic approach?

· If a probabilistic approach was used, was there an analysis of the expected value of perfect information?

· Did the study use any other forms of sensitivity analyses (e.g., scenario analyses on model uncertainty)?

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Reporting Sensitivity Results

· Were the main results sensitive to the sensitivity analyses results?

· Was heterogeneity within subgroups assessed?

· Implications for generally cost-ineffective interventions with potential value for high-risk groups

· Important for evaluating an intervention's potential health disparities effects

Reference Case and Reporting Guidelines

Importance of Reference Case

· Necessary for critical review of economic evaluations

· Foundation upon which modern methodological advice is built

· Considered standard practice

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Why Use a Reference Case?

· Lack of transparency and quality are barriers to utilization of economic evaluation studies.

· Transparency for lay and technical audiences helps ensure quality.

· The wide range of underlying assumptions used in modeling studies is a barrier to assessing quality.

· For comparisons of different studies of the same intervention to be meaningful, the methodologies underlying the results are comparable.

· Prescriptive reporting guidelines aid in transparent communication.

· Agreed-upon preferred analytic methods are needed.

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Why Use a Reference Case? (cont.)

· The elements should be included in every analysis.

· This still allows analysts to report alternative results using different methods while promoting comparability in the field.

· The reference case developed by the U.S. Public Health Service Panel on Cost-Effectiveness in Health and Medicine is a guiding document.

· A second panel will be updating these guidelines in 2016 after 20 years of use in the field.

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Core Element 1: Societal Perspective

The societal perspective should be adopted.

· Taking a narrow perspective that includes either healthcare system or patient costs and outcomes may not adequately capture the costs and outcomes of a health-promotion intervention.

· Societal perspective captures:

· All benefits and harms of the intervention in the outcome, even if they do not accrue to the intended recipients

· The costs of all resources, regardless of who pays and even if no money changes hands

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Core Element 2: Benefits and Harms

Effectiveness estimates should incorporate benefits and harms.

· Corollary to societal perspective

· Narrowly considering only the benefits to target population could ignore harms to others.

· Example: Folic acid fortification potentially masking pernicious anemia in elderly populations

· An intervention can have unintended negative consequences for a group that was not the intended target.

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Core Element 3: QALYs

Mortality and morbidity consequences should be combined using quality-adjusted life years (QALYs).

· Example of hypothetical cancer therapy

· Ignoring health-related quality of life (HRQoL) by focusing narrowly on life years obscures critical information on treatment effectiveness.

· Use of disability-adjusted life years (DALYs) widely accepted

· Analysts may consider reporting both QALY and DALY results when feasible.

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Core Element 4: Sources

Effectiveness estimates from best-designed and least-biased sources should be used.

· This highlights the importance of causally strong systematic review and meta-analysis techniques in the field.

· The utility of trial-based evaluations is limited if the effectiveness results deviate widely from the best evidence in the broader field.

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Core Element 5: Costs

Costs should include healthcare services, patient and caregiver time, and costs of nonhealth impacts.

· This is closely related to the adoption of the societal perspective.

· It is important to capture the costs from all of these sectors.

· Costs should be reported separately to help identify barriers to adoption of cost-effective interventions.

· Who pays is not always (or often not) who benefits from public health interventions.

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Core Element 6: Comparison

Comparison should be made with existing practice and, if necessary, a viable low-cost alternative.

· Comparison to current practice directly relates to the decision context, but may be misleading if current practice is based on ineffective or expensive interventions.

· Anything will look cost-effective if compared to a sufficiently bad alternative.

· Status quo bias should not require us to limit the consideration of alternatives to current bad practice.

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Core Element 7: Discounting

Discounting of costs and health outcomes should be undertaken at a real rate of 3% per year (with 5% as an alternative scenario).

· Debate continues about the "best" discount rate as well as whether health and cost outcomes should discounted at the same rate.

· But there is general consensus on uniform discount rates.

· Using a reference discount rate is critical for comparability.

· Rate may vary based on different decision-making contexts.

· Analyses should include the reference rate for broader comparability.

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Core Element 8: Sensitivity

One-way and multiway sensitivity analysis should be undertaken for important parameters.

· Guideline replaced by the general practice of conducting probabilistic sensitivity analyses

· Limits of using one-way or even multiway sensitivity analyses noted

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Core Element 9: ICER

Comparison of the ICER should be made with those for other relevant interventions.

· Broadly applicable

· Requires consideration of the most relevant alternative

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Reporting Guidelines

· Consolidated Health Economic Evaluation Reporting Standards (CHEERS) Task Force

· Developed to be consistent with CONSORT methodology for reporting results from clinical trials

· Are largely consistent with guidelines previously reviewed

· Contain additional detail on reporting economic evaluations within context of clinical study, as opposed to when using decision-analytic model

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Reporting Guidelines (cont.)

· National Institute of Health and Care Excellence (NICE)

· Ensure minimum methodological standards

· Improve comparability across submissions

· World Health Organization (WHO)

· Used extensively outside of Europe and North America

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ISPOR Guidelines

International Society for Pharmacoeconomics and Outcomes Research

· ISPOR has more than 30 sets of guidelines and continues to provide additional guidance.

· These guidelines are:

· "Official" (i.e., intended for making reimbursement decisions)

· Technical guidance for academics to improve the quality of research

· ISPOR collaborated on a task force with the Society for Medical Decision Making, issuing a series of articles on Modeling Good Research Practices that update the technical aspects of the original reference case guidance.

Model Validation Principles

Importance of Transparency

· Clearly describes the model structure, equations, parameter values, and assumptions

· Enables interested parties to understand the model

· Establishes foundation upon which model evaluation is based

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ISPOR Task Force Reporting

International Society for Pharmacoeconomics and Outcomes Research (ISPOR)-SMDM

· Transparency and validation are required components of full model evaluation.

· Validation is subjecting the model to tests, such as comparing model results with events observed in reality.

· If transparency helps readers understand what a model does and how it does it, validation is the only way for readers to determine how well it works.

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Multiple vs. Single Application Models

· The effort put into building a comprehensive model of disease epidemiology and related health and healthcare costs makes using the same model to evaluate multiple interventions attractive if only to realize some economy of scale.

· More importantly, using the same model to evaluate a range of interventions provides a level methodological field so that variation in ICERs across interventions should be due primarily to intervention-specific inputs and assumptions instead of variation in underlying modeling approaches.

· For these types of models, there is a distinction between validation focused on underlying methods and validation of a specific application of the model.

· Because there is no set of criteria that makes a model "valid," the concept of validation should apply to the specific application, not to the model itself.

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Five Types of Validation

1. Face validity

2. Verification (or internal validity)

3. Cross-validity

4. External validity

5. Predictive validity

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Face Validity (cont.)

· Was once a core component of validation in scale development

· It has fallen out of the nomenclature given its subjectivity.

· ISPOR-SMDM notes that as currently practiced, peer review is insufficiently consistent to be relied on for determining face validity.

· Included in current best practice recommendations, despite limitations

· Should include description of process

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Verification

· Also called internal validity, consistency, or technical validity

· Is a two-step process:

· Verifying individual equations

· Verifying accurate implementation in code

· Should be aligned with best practices in software development

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Cross-Validation

· This is also called external consistency.

· This involves:

· Examining different models that address the same problems and comparing the results

· Examining the differences and their causes

· If different models are highly dependent (i.e., use parameters from other models), the value of cross-validation decreases.

· Modelers should:

· Search for modeling analyses of the same or similar problems

· Discuss insights gained from similarities and differences in results

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External Validation

· Compares a model's results to actual event data

· Involves simulating events that have occurred, often from a clinical trial

· Could apply to the model as a whole or to components such as:

· Population creation

· Disease incidence

· Disease progression

· Outcome occurrence

· Intervention effects

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Calibration: Subcomponent of

External Validation

· In a modeling context, refers to ensuring that inputs and outputs are consistent with available data

· Is important for unobservable intermediate parameters

· Commonly, matches output to external data and adjusts model parameters to achieve a fit with known outcome

· Should include in reporting

· Target

· Goodness-of-fit metric

· Search algorithm

· Acceptance criteria

· Stopping rule

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Predictive Validation

· Involves:

· Identifying an opportunity in which a study design can be well-specified and simulated while reporting the outcome before the outcome occurs

· Comparing the predictions to what actually happened

· Is an important test for multiple-use models that are attempting to inform a broad set of specific applications

· Can be most easily done based on well-reported clinical trial designs that are reported before results are released

· Is much harder to achieve in health-promotion interventions

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Evaluating Validation

Users of models should examine validation results for:

· Rigor of the process

· Quantity and quality of sources used

· How well sources represent model's proposed use

· Model's ability to simulate sources in appropriate detail

· Closeness of results to observed outcomes

Priority-Setting Principles

Complex Global Context

· Growing evidence of poor use of limited health resources

· Rising healthcare expenditures

· Increasing doubts about "free" market as the mechanism for health resource allocation, access to health/health outcomes

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Priority Setting

· Attempts to maintain the clear benefits of economic evaluation by incorporating other resource-prioritization approaches

· Is a recognized field that deals with rationing, but lacks consensus on best methods

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Models of Priority Setting:

Normative Advice

· Behavioral science (achieving consensus)

· Epidemiologists/clinicians (needs assessment)

· Philosophers (social justice)

· Economists (efficiency)

· Administrators (feasibility, historical allocation)

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Choosing From Conflicting

Normative Advice

Assessing Cost-Effectiveness (ACE) framework (Rob Carter et al.) is the basis of an "ideal" approach to priority setting.

· Economic theory: guidance on choices amidst resource scarcity

· Ethics: standards for judging societal welfare

· Empirical evidence and user considerations for relevance

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Economic Theory

· Provides theoretical rationale for better-to-worse alternative ranking

· Bases rank on an allocative efficiency assessment reflective of societal values

· Overlaps with ethics definition of societal welfare

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Economic Approaches

· Welfare economics: favors individual preferences and role of the market

· Extra-welfarism: is health-based, conducive to government intervention and judgment by health professionals

· Decision-making approaches (DMA): focus on the decision-maker as arbiter

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The welfarist focus on individual utility and the extra-welfarist focus on health needs should be supplemented with information on other social concerns, such as need, health status, equity, and procedural justice.

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Ethics and Social Justice

· Like economics, uses logical argument with explicit assumptions

· Unlike welfarism, sometimes rejects the role of community preferences in moral judgments

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Ethical Approaches

· Deontology: duty, process, and individual rights

· Consequentialism: outcomes and collective good

· Distributive justice: impartial, fair balance of competing individual claims

· Combination based on background, experience, and choice problem and setting

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Empirical Experience

· Is commonly used but not as a purely technical approach

· Values efficiency but not at the expense of other objectives

· Strives to balance economic techniques and decision rules with due process and consultation

· Suffers from technical barriers (e.g., lack of data), can limit scope

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User Considerations

· Aims to deliver services to people who will benefit

· Creates guidelines for matching patients to treatment types and intensity levels

· Focuses on evidence-based clinical and public health practices rather than efficiency-based care rationing

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What Is the Best Approach?

While decision-making approaches cannot ignore economic evaluation, policy makers and the public reject those which rely exclusively upon it.

ACE Prevention Priority Setting Example

ACE Prevention Study

· In 2010, the Assessing Cost-Effectiveness (ACE) in Prevention study issued a final report of five-year effort to evaluate cost-effectiveness of prevention investments in Australia.

· Funded by Australian National Health and Medical Council

· Led by Theo Vos and Rob Carter of University of Queensland and Deakin University

· Developed to address the challenges of aging population.

· With consideration of increasing budget pressures

· With a focus on identifying best values in prevention

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ACE Prevention Study (cont.)

· Focused on achieving a more efficient and fairer prevention system

· Addressing deep health inequalities facing indigenous Australians

· Allocating prevention resources to reduce inequities

· Was the largest and most rigorous evaluation of preventive strategies at the time

· Is still a model for using economic evaluation to develop broad health-promotion prioritization strategies

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ACE Prevention Study: Details

· Evaluated 123 prevention interventions and 27 treatment interventions

· Adapted the general population model to evaluate the cost-effectiveness of 21 interventions specifically for indigenous population

· More than doubled the total number of economic evaluations of health promotion and illness prevention in Australia

· Placed results in broader priority-setting context by:

· Getting guidance from stakeholders in government, health nongovernment organizations, academia, and service providers

· Having stakeholders help formulate conclusions by combining technical results with other policy-relevant considerations such as acceptability, feasibility, and equity

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Findings: Impact

Large impact on population health could be achieved with a limited number of cost-effective interventions.

· Taxation of tobacco, alcohol, and unhealthy foods

· Regulation of sodium in bread, cereals, and margarine

· Improving efficiency of blood pressure and cholesterol-lowering drug prescription

· Gastric banding for severe obesity

· Intensive sun-exposure-prevention campaign

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Findings: Second-Stage Filters

Technical findings were combined with second-stage filter considerations.

· The evidence varies.

· "Likely" for taxation and regulation

· "Sufficient" for treatment interventions

· "Limited" for sun-exposure campaign

· Taxation and regulation have low implementation costs but high political costs.

· Proposed changes to blood pressure and cholesterol prescribing have challenges to stakeholder acceptability.

· Government subsidies for gastric banding requires additional guidelines on best practices.

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Findings

· 43 were either cost-saving or cost less than $10,000 per DALY prevented.

· These should only be ignored if there were serious reservations about the evidence base or insurmountable problems related to acceptability or feasibility.

· 31 provided good value compared to a threshold of $50,000 per DALY prevented.

· 38 were expensive compared to the threshold of $50,000 per DALY prevented.

· Of these, four had insufficient evidence, two were associated with more harm than benefit, and two were dominated by more cost-effective alternatives.

The authors concluded that prevention interventions are not always good value and are not always better than treating disease.

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Separate Indigenous Analysis

· Conducted because of differences in many key evaluation parameters

· Target disease burden

· Prevalence and distribution of harmful exposures

· Effectiveness of intervention strategies

· Models of health service delivery

· Acceptability to stakeholders

· Cost of implementation

· Identified meaningful differences in population's health priorities

· Community health gain

· Cultural security

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Recommendations

· Increase tax on tobacco by 30%.

· Change to volumetric tax on alcohol.

· Implement 10% tax on unhealthy foods.

· Enact mandatory regulation of salt in bread, margarine, and cereal.

· Disinvest in prevention activities found to be not cost-effective, including:

· Current cardiovascular preventive treatment

· PSA testing for prostate cancer

· Aspirin for primary prevention of cardiovascular disease

· Most approaches for promoting fruit and vegetable intake and weight-loss programs

· School-based illegal drug interventions