GC650 Lecture 3 - Measuring Effectiveness

Clinical Measures of Effectiveness Examples (7)

1. Hospitalizations avoided

2. ER visits avoided

3. Healthy days

4. LDL goal attainment

5. Blood pressure goal attainment

6. Progression Free Survival

7. Overall Survival

Patient Focused Measures of Effectiveness Examples (4)

1. Health-related quality of life

2. Patient satisfaction with treatment

3. Patient preference

4. Productivity (self-reported)

WHO Health Definition

A state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.

WHO Quality of Life Definition

An individual’s perceptions of their position in life in the context of the culture and value system in which they live and in relation to their goals, standards, and concerns. This extends beyond health.

Use of Quality of Life Measures in PROs and RCTs

QoL endpoints can be a better indicator of health than clinical measures, pain is subjective, and EQ-5D is increasingly common

Why measure quality of life? (3 Perspectives)

1. Assess impact of illness

2. Assess impact of treatment

3. Inform what a clinically meaningful difference is on objective measures

Types of Quality of Life Instruments (2)

1. Health Profile Measures - SF36

2. Health Utility or Preference Measures - EQ-5D

SF-36 Domains (2 Overarching)

1. Physical Health

2. Mental Health

SF-36 PCS Subcategories (4)

1. Physical Functioning

2. Role-Physical

3. Bodily Pain

4. General Health

SF-36 MCS Subcategories (4)

1. Vitality

2. Social Functioning

3. Role-Emotional

4. Mental Health

Quality Adjusted Life Year (QALY)

Measures both the quantity (duration) of life and the quality of life, need to know how much people value a year of life in a particular health state

Typically uses the EQ-5D

QALY is a measure of…

Health Utility

Steps to Developing Health Utilities

1. Select method for describing health

2. Develop weights for valuing each health state

3. Combine the weights with life expectancy in the health state to calculate good years remaining or years lost

EQ-5D Dimensions (5)

1. Mobility

2. Self-Care

3. Usual Activities

4. Pain/discomfort

5. Anxiety-depression

Old version had 3 levels (243 states), new has 5 (3215 states). Higher numbers are worse health states.

Time Trade Off Calculation

You will live the next 10 years with a disease. How many years of life are you willing to give up to have perfect health?

Ex. Give up 2 years. 8 Years Remaining/10 Years Total. Each disease year is worth 0.8 healthy years.

Shaw Calculation

Based on the 4,000+ respondents from the Shaw study, uses their collective answers to weigh health states.

Adding up each deviation above 1 and doing a calculation using the regression from their study.

EQ-5D Visual Analog Scale (VAS) Calculation

Patient rates their health on a scale of 1 to 100, divide the answer by 100 to get the value of time in that health state.

QALY Calculation

(time in that quality of life state) x (individual’s utility for life during that time)

Example QALY: Good Health with Minor Comorbidity in older years

Multiply the value of each category by the number of years spent in that category to get QALY

Total in the picture is 72.4 QALY out of 82 Years

Societal Value of a Treatment Calculation

The sum of QALYs experienced by individuals with the disease and receiving the treatments/programs of interest

When to Measure Quality of Life?

Ideally you want to know what a person’s Quality of Life is before, during and after an intervention.

Some conditions/treatments have different stages or exacerbations, so you would want to know the quality of life for any changes in the health state

Ethical Considerations of Measuring Quality of Life (5)

1. Source of the value/weighting scheme

2. Age weighting

3. Failure to give priority to those in worst health

4. Discriminate against those with limited treatment potential – because the score cannot be improved with intervention

5. Fail to account for qualitative differences in outcome

Disability Adjusted Life Year (DALY)

It represents the total years of healthy life lost due to illness, disability, or premature death.

Includes Years of Life Lost (YLL) and Years Lived with Disability (YLD).