Indicators of Health Status

Introduction

Health status refers to >”An individual’s or a population’s overall health, taking into account various aspects such as life expectancy, amount of disability and levels of disease risk factors.” (AIHW, 2008)

Health indicators are >”standard statistics that are used to measure and compare health status” (e.g. life expectancy, mortality rates, morbidity rates).
* These indicators provide valuable information about the health of a population, allowing for comparisons over time and between different groups.

KEY TAKEAWAY: Health indicators are crucial for assessing and comparing the health of populations.

Mortality

Mortality refers to death, particularly at a population level. Mortality rates are usually expressed per 1,000 or 100,000 people.

Types of Mortality

• Infant Mortality Rate (IMR): The number of deaths of infants before their first birthday, per 1,000 live births.
  • IMR is a sensitive indicator of the overall health of a population, reflecting factors like access to healthcare, nutrition, and sanitation.
• Under-Five Mortality Rate (U5MR): The number of deaths of children before their fifth birthday, per 1,000 live births.
  • U5MR is another key indicator of child health and well-being.
• Maternal Mortality Ratio: The number of maternal deaths per 100,000 live births. Maternal death is defined as the death of a woman while pregnant or within 42 days of termination of pregnancy, irrespective of the duration and the site of the pregnancy, from any cause related to or aggravated by the pregnancy or its management, but not from accidental or incidental causes.
  • Maternal mortality reflects the quality of maternal healthcare services.

EXAM TIP: Be able to define each mortality rate and explain what factors influence it.

Morbidity

Morbidity refers to the level of illness or disease in a population.

• It includes various aspects, such as the incidence, prevalence, and types of diseases present.

Incidence and Prevalence

• Incidence: The number of new cases of a disease or condition in a population during a specific period. Often expressed per 1,000 or 100,000 people.
• Prevalence: The total number of cases (new and existing) of a disease or condition in a population at a specific time. Often expressed as a percentage or per 1,000 or 100,000 people.

COMMON MISTAKE: Confusing incidence and prevalence. Remember incidence refers only to new cases.

Burden of Disease

Burden of disease measures the impact of diseases and injuries on a population. It takes into account both the years of life lost due to premature death and the years lived with disability.

Disability-Adjusted Life Year (DALY)

The Disability-Adjusted Life Year (DALY) is a measure of burden of disease. One DALY represents one year of healthy life lost due to illness, disability, or premature death.

The DALY is calculated as the sum of:
* Years of Life Lost (YLL) due to premature mortality.
* Years Lived with Disability (YLD) due to illness or injury.

$$DALY = YLL + YLD$$

Years of Life Lost (YLL)

Years of Life Lost (YLL) represents the number of years of life lost due to premature death. It is calculated by subtracting the age at death from the expected life expectancy at that age.

Years Lived with Disability (YLD)

Years Lived with Disability (YLD) represents the number of years lived with a disability, weighted by the severity of the disability. The weighting factor ranges from 0 (perfect health) to 1 (death).

STUDY HINT: Practice calculating DALYs using hypothetical scenarios to understand the concept better.

Life Expectancy and Health-Adjusted Life Expectancy (HALE)

Life Expectancy

Life expectancy is >”the number of years of life, on average, remaining to an individual at a particular age if death rates do not change. The most commonly used measure is life expectancy at birth” (AIHW, 2018).

• It is an indicator of the overall health status of a population.

Health-Adjusted Life Expectancy (HALE)

Health-Adjusted Life Expectancy (HALE) is the number of years a person can expect to live in full health, taking into account years lived with disability or illness.

• HALE provides a more comprehensive measure of health status than life expectancy alone.
• It reflects both the quantity and quality of life.

REMEMBER: HALE considers the quality of life, while life expectancy focuses on the quantity.

Self-Assessed Health Status

Self-assessed health status is a measure based on a person’s own perception of their health.

• Individuals are asked to rate their health, typically on a scale (e.g., excellent, very good, good, fair, poor).
• While subjective, self-assessed health status is a useful indicator of overall health and well-being, and is often correlated with other health indicators.

APPLICATION: Self-assessed health status can be used to identify populations at risk and to evaluate the effectiveness of health interventions.

Summary Table of Indicators

VCAA FOCUS: VCAA often asks questions about interpreting data related to these health indicators and comparing health status across different population groups.