Health Indicators

objectives By the end of this lecture students should know the: 1-Definition of health indicator. 2-Types of health indicators. 3- Tools of disease measurement. 4-Disease incidence. 5-Disease prevalence.

An indicator is defined as a measure of disease , death or any other event of life. It is also used to compare the occurrence of disease ,death or any other event between targeted communities or countries.

Indicators of health: 1.Mortality indicators. 2.Morbidity indicators. 3-Natality indicators. 4.Disability indicators. 5.Nutritional status indicators. 6.Health care delivery indicators. 7.Utilization indicators. 8.Indicators of social & mental health. 9.Environmental indicators.

10.Socio-economic indicators. 11.Health policy indicators. 12.Indicators of quality of life. 13.Other indicators :- Health for all indicators. Social indicators. Basic needs indicators.

1-Rate 2-Ratio 3-Proportion 4-Counts 5-Percentage% Tools of Measurements: ادوات القياس The three main measures we use are : -Rate Ratio and proportion. 1-Rate 2-Ratio 3-Proportion 4-Counts 5-Percentage% Measures of disease frequencies come in five main categories. These measures are used to relate the number of cases of outcome to the size of the source population from which they occurred

Example of disease measurement Diseased 1) How many people have a disease? 2) What proportion of the population has disease? Not Diseased An important task of epidemiology is to compare causes or distributions of disease or death in populations. We often use measures of frequency to describe the causes and patterns of disease, or any other event related to health in human populations. An example of the questions that are often asked may include: How many people have a disease What percentage of the population that has a disease What proportion of the population could still get the disease

RATE The rate measures the occurrence of disease or death or any other events in a population during a given time period .

Example of Rate :- 1-Death Rate = Number of deaths in one year x 1000 Mid-year population 2-Birth Rate = Number of live births in one year x 1000 It comprises these elements :- Numerator Denominator (the numerator is a component of the denominator) Time specification (usually a calendar year.) Multiplier

RATIO Ratio is a relation in size between two quantities . The numerator is not component of the denominator

Examples of Ratio It is expressed in the form of : X : Y OR X / Y For example: The ratio of WBCs relative to the RBCs is 1 : 600 or 1/600 What is the ratio of females to males (sex ratio) ? Number of Females = 2,5 : 1 Number of Males This is an example of a ratio that is commonly used in public health and other disciplines, the sex ratio. The sex ratio compares the proportion of females/males or males/females. In this example, there are 5 women and 2 men. Therefore, the ratio is calculated by dividing 5/2 to receive a proportion of 2.5 to 1. = 5 / 2 = 2,5 / 1

Other examples of ratio :- Doctor – Population ratio. Example (2) of ratio :- The number of children with scabies at a certain time The number of children with malnutrition at a certain time x 100 Other examples of ratio :- Doctor – Population ratio. Child – Woman ratio.

Proportion The proportion is a relationship between a part from the whole Numerator IS INCLUDED In the denominator Quantities have to be of the same nature The proportion is usually expressed as a percentage. A proportion is one number divided by another number in which those who are included in the numerator must also be included in the denominator. A proportion ranges from 0-1, but this measure can also be expressed as a percentage ranging from 0-100%. Here is another example using the female population. As you can see the proportion is calculated by dividing two by four, which equals 0.5 or 50%. The women included in the population listed above are both in the numerator and the denominator. However, rates are often used more loosely in epidemiology to refer to proportions that are not truly rates (e.g. attack rate or case-fatality rate) 2 --- = 0.5 = 50% 4

Example of proportion : The number of children with scabies at a certain time x100 The total number of children in the village at the same time

1- Morbidity Indicators Morbidity indicators measure the occurrence of disease in a population. Incidence Rate Prevalence Rate

Prevalence and Incidence Let us discuss the relationship between prevalence and incidence, and the differences between the two measures. This beaker of water illustrates the relationship. The level of water in the beaker represents the prevalence of, say, HIV‑infected persons. This level is a function of the rate at which new infections pour into the beaker, representing incidence, as well as the rate at which water leaves the beaker, representing losses to the population due to mortality or moving out of the community. If no deaths or recovery occurred, then the water level, representing the prevalence, would increase over time at the rate of the entry of the incoming water representing new infections. On the other hand, if there were no new cases and water stopped entering the beaker (or new cases of HIV stopped occurring), prevalence would decline as water left the beaker. If the inflow and outflow to the beaker are balanced, even if at very high levels, then a stable level of water would occur. In such a situation, a stable prevalence rate could mask a very high incidence rate. Since epidemiologists and public health officials are concerned about preventing new infections, incidence is generally a better measure to use to monitor how rapidly a disease is spreading. The problem with incidence, of course, is that it requires one to follow cohorts of specific individuals through time to measure new onset of disease. In most cases this is very expensive and not practical. Recovery Death

Incidence Measure of new cases of disease (or other events of interest) that developed in a population during a specified period of time. Incidence Rate = Number of new cases of specific disease during a given time period _____________________________ ×1000 Population at risk during that period

Example of incidence rate : - The number of new cases of an illness is 500 in a Population of 30,000 in one year. Incidence Rate is : - 500 /30,000 × 1000 = 16,7 per 1000 per one year

Types of Prevalence Prevalence Number of all existing cases of disease( old and new cases) in a population. Types of Prevalence Point prevalence: number of all cases ( old and new cases) that exist at a given point in time Period prevalence: number of all cases ( old and new cases) that exist in a population during a specified period of time

Point prevalence :- number of all cases(old + new) of specific disease during a given point in time _______________________________ × 1000 population at risk during that period Period prevalence :- number of all existing cases(old + new) of specific disease during a given period of time interval

Relationship between prevalence and incidence Prevalence =Incidence × Duration P =I × D I = P / D D=P / I Example :- Incidence = 10 cases per 1000 per year Duration of disease = 5 years Prevalence = 10 × 5 = 50 per 1000 population

2- Mortality Indicators Mortality indicators measure the occurrence of deaths in a defined population during a specified period of time. Examples of mortality indicators(crude + specific) :- 1- Crude Death Rate = number of deaths in one year ×1000 Mid – year population It measure the mortality rate from all causes of death for a population.

Example of specific death rate :- 2- Specific death rate due to tuberculosis :- Number of deaths from tuberculosis in one year ×1000 Mid- year population

Infant Mortality Rate (IMR) :- IMR = number of deaths among children under 1 year of age in a given year ×1000 number of live births during the same year It measures the efficacy of health care services in a country.

Maternal Mortality Rate ( MMR) :- MMR = Number of maternal deaths due to causes related to pregnancy ×100,000 Number of live births during the same time period MMR measures the mortality associated with pregnancy. It is less common than IMR , so it is expressed per 100,000 . E.g. 20 maternal deaths per 100,000 live births.

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