cost utility analysis

Presenter Information
- Lorenzo Villa Zapata, PharmD, PhD
- University of Georgia - College of Pharmacy

Definition of Cost Utility Analysis (CUA)
  - CUA is a subset of Cost-Effectiveness Analysis (CEA).
  - Outcomes are assessed using a specific clinical outcome measure, primarily the Quality-Adjusted Life-Year (QALY).
  - CUA incorporates patient preferences, termed utilities, which factor into the measurement of health consequences.
Utility Defined
- The term utility, while having a precise definition in economics, is generally used across disciplines to refer to the personal or group preferences related to health outcomes.

Types of Cost Analysis
  - Cost-Minimization Analysis
    - Cost Unit: Dollars (or Other Currency)
    - Outcome Measurement: Same Therapeutics Outcomes
  - Cost-Effectiveness Analysis
    - Cost Unit: Dollars (or Other Currency)
    - Outcome Measurement: Natural Effectiveness Units such as mmHg, mg/dL, or years of life gained
  - Cost-Benefit Analysis
    - Cost Unit: Dollars (or Other Currency)
    - Outcome Measurement: Dollars (or Other Currency)
  - Cost-Utility Analysis
    - Cost Unit: Dollars (or Other Currency)
    - Outcome Measurement: Quality-Adjusted Life Years (QALY)
  - Reference: "Methods for the Economic Evaluation of Health Care Programmes" (2005) by Michael F. Drummond, Mark J. Sculpher, George W. Torrance, Bernie J. O'Brien, Greg L. Stoddart.

Concept of Quality of Life
  - Quality of life encompasses various domains affecting an individual's or group's subjective assessment of the impact of their health or therapy on functioning and well-being.
  - Factors include:
    - Social role
    - Environment
    - Family
    - Mental well-being
    - Physical health
    - Biological functions
    - Social status and relationships
    - Work life
Definition of Health-Related Quality of Life (HRQoL)
- HRQoL is specifically concerned with the health impacts on general well-being.

Examples of Clinical Effectiveness Measures
  - Quality-Adjusted Life Year (QALY):
    - A widely used health outcome measure for assessing the value for money of medical interventions.
    - It serves as a generic measure of disease burden, considering both quality and quantity of life lived.
  - Utility:
    - Representing a quality measure, utility indicates the preference or value assigned to a particular health state by an individual or society, typically on a scale of 0 (representing death) to 1 (indicating perfect health).
  - Life Years (quantity measure):
    - Measures the number of years lived but does not account for the quality of life during those years.
    - A treatment that increases QALYs will do so by increasing both the longevity and health quality.

QALY Calculation Formula
- The formula to calculate QALYs is:
$\text{QALYs} = \text{Years of Life} \times \text{Utility Value}$
Example Calculation
  - If an individual lives in imperfect health with a utility of 0.8 over a span of 5 years:
    - Calculation:
       $5 \text{ Years of Life} \times 0.8 \text{ Utility Value} = 4 \text{ QALYs}$
  - Note: Utilities may vary over time, complicating calculations.

Comparison of Two Treatments
  - Treatment 1: HepSlow
    - 2.5 years of chronic hepatitis B symptoms (utility = 0.68)
    - 0.5 years of decompensated cirrhosis (utility = 0.35)
    - 0.75 years of liver transplant first year (utility = 0.57)
    - Calculation of total QALYs:
       $2.5 \text{ years} \times 0.68 + 0.5 \text{ year} \times 0.35 + 0.75 \text{ years} \times 0.57 = 2.3025 \text{ QALYs}$
  - Treatment 2: ImprovedHepBCare
    - 2.75 years of chronic hepatitis B symptoms (utility = 0.68)
    - 0.25 years of decompensated cirrhosis (utility = 0.35)
    - 1 year of liver transplant first year (utility = 0.57)
    - Calculation of total QALYs:
       $2.75 \text{ years} \times 0.68 + 0.25 \text{ years} \times 0.35 + 1 \text{ year} \times 0.57 = 2.5275 \text{ QALYs}$
  - QALYs Gained:
    - Difference in QALYs between the two treatments:
       $2.5275 - 2.3025 = 0.225 \text{ QALYs gained}$

EQ-5D-3L Overview
  - The EQ-5D-3L is a standardized instrument for measuring health outcomes. It includes:
    - 5 Dimensions of health:
      1. Mobility
      2. Self-care
      3. Usual activities
      4. Pain/discomfort
      5. Anxiety/depression
  - Utility Value Example
    - A sample EQ-5D-3L score could be Me: 11122, yielding a utility of 0.800.
  - Each dimension of health is rated on three levels:
    - No problems
    - Some/moderate problems
    - Extreme problems