Module 2 Section 5

Question 1

Taking Quality of Life into Account

Answer 1

Measures of prevalence and incidence are a poor indicator by themselves because they don’t indicate how many people died from the disease. Mortality is slightly better in that regard, but it doesn’t indicate anything about the age that people die of a specific disease or their quality of life
While there are several metrics for measuring disease burden, the most accepted metric for global burden of disease (GBD) is the Disability Adjusted Life Year (DALY), which is used by the WHO

Question 2

Disability Adjusted Life Year (DALY)

Answer 2

• This video explains the concept of Disability-Adjusted Life Years (DALYs), a measure used in public health to quantify the burden of diseases. It begins by presenting a scenario where a health ministry is offered $100 million in additional funding, with the condition that it be used for high-value disease intervention strategies. The challenge is to demonstrate that diseases like diabetes, which may differ in various aspects (e.g., populations affected, complications, treatments) from diseases like AIDS, also offer significant health burdens and could benefit from intervention programs.
• The video introduces DALYs as a standardized metric that combines both mortality (years of life lost due to premature death) and morbidity (non-fatal effects like illness or disability). The DALY score is calculated by summing the years of life lost (YLL) and the disability-adjusted life years (DALY). The video provides an example of how diabetes burden is quantified: a person dying at 60 years old instead of 75, plus the disability caused by the disease, results in a total DALY score.
• DALYs allow for comparisons between diseases, interventions, and populations. The metric helps quantify the health burden of diseases, compare different interventions (such as treatment versus prevention), and make cost-effectiveness analyses. The video concludes by emphasizing that DALYs play a significant role in global health policy, enabling better decisions about health priorities and interventions.

Question 3

Calculating DALY

Answer 3

Disability Adjusted Life Year (DALY) is a measure of overall disease burden, expressed as the cumulative number of years lost due to ill-health, disability, or early death

Disability Adjusted Life Year (DALY) = Years Lived with Disability (YLD) + Years of Lost Life (YLL)

Question 4

Years Lived with Disability (YLD)

Answer 4

To incorporate disability and mortality into a single measure of burden, years lived with disability (YLD) is used. YLD multiplies the number of years a person has a condition that affects their quality of life. Each condition has a weighting factor between 0 and 1, 0 being perfect health and 1 being death. The rating is indicative of the degree to which a disease negatively impacts an individual’s life

YLD = prevalence x disability weighting factor

Question 5

Years of Life Lost

Answer 5

Years of life lost (YLL) is an indicator of premature mortality and has two defining characteristics:
1. It takes age of death into account by subtracting life expectancy by the average age of death
2. It places more weight on illnesses that result in early mortality because dying younger has a bigger impact on both the individual and society at large

YLL = (# of deaths) x (Life Expectancy – Death)

Question 6

Criticisms of DALY

Answer 6

While widely accepted by many, the use of DALYs has also received criticisms.

Criticisms
- it evaluates health through an ableist lens
- By weighting disability, able-bodied people are valued more highly than people with disabilities
- doesn’t account for the age of people, which is related to a person’s ability to contribute to society.
- Through a second weighting scheme (not discussed in this section), DALY can be adjusted for age such that middle-aged years have the highest weighting

Support
- Supporters of DALY counter criticisms by pointing out that prioritizing interventions based on people’s potential to contribute to society is currently the best option