Health Indices

8/14/2019 Health Indices

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dr/Dalia Ahmed Mohamed


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Vital statistics

By

Dalia Ahmed Mohamed

Assistant Professor of Public Health


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Past-Where have we been?


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Present Where are we now?


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Future-Where are we going?


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Morbidity Statistics

There are two basic measures to assess thefrequency of the disease:

A. Incidence rate:

B. Prevalence rate:

A RATE is composed of a numerator (number ofevents), a denominator (population at risk for theevent) and the specified time in which events occur(in case of incidence rate) or the specific time inwhich the data were collected (in case of prevalencerate) and a multiplier(constant: 100, 1000, 100,000)

Most rates are proportions: the numerator is a subsetof denominator


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Incidence Rate

It is the number of new (reported) cases of aparticular disease over a certain time period

and locality per 1000 at-risk population in the

same time period and locality

Example: Incidence of acute meningitis in Egypt 1995=

No of reported cases of meningitis throughout year 1995 in Egypt X 100, 1000

Total at-risk population in Egypt year 1995


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Incidence Rate

Measures the amount with which unaffected persons developa particular disease(newly diagnosed cases ) per unit ofperson-time

It is usually used in measuring the frequency of acute

diseases (communicable) per time Measuring the incidence of chronic diseases done through

follow up of disease-free individuals and detection of cases

throughout time.

The decrease in the incidence rate may be due to : enhancedresistance to disease, change in the disease etiology, an

effective prevention program for infectious diseases (e.g.

immunization) or program that reduces exposure to a risk factor

for the disease( antismoking program and cancer lung)


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The attack rate

is a type of the incidence rate where the

frequency of occurrence of a disease

for the same individual is considered.Example: the attack rate of diarrhea

was 40 attacks per 1000 under-five

children per year.


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Prevalence Rate

It is the number of all cases [new and old] of

a particular disease diagnosed during a

survey study in a given locality (area) during acertain time period per 100 examined at-risk

individuals.

Example: Prevalence of Diabetes in Egypt 1994=

No of new and old cases ( 20 years of age) X 100

Total Number of examined individuals ( 20 years of age)


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Measures the amount of disease alreadypresent in a population

It is a good measure for chronic diseases as it

measures the accumulated cases by time forboth the new and old cases.

It is used for measuring the prevalence of non-

communicable diseases and some

communicable diseases (e.g. TB, Bilharziasis)

Prevalence Rate


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Prevalence Rate

Survey studies (using screening

tests/diagnostic tests) are conducted to

measure the prevalence of the diseaseswhere reporting and registration are lacking

Proper clinical examination and investigations

provide accurate data about the prevalence.

Personal interviews provide underestimationof the prevalence rate


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Prevalence Rate

The prevalence of the disease depends on itsincidence rate and the duration of illness

High prevalence may be due to high incidence or longduration of the disease

Successful control of the diseases with no cureprologs life and increase the prevalence

Low prevalence may be due to low incidence, shortduration (rapid recovery or death) or both

Successful treatment with complete recovery (cure) orthe occurrence of disease complications that lead torapid death, decrease the prevalence rate


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Disease Burden Measurement of the disease burden depends on the

time (years) lost due premature death and the time

lived with disability.

The Disability Adjusted Life Years (DALYs) for aspecific health problem in the population equal:

sum of years lost due to premature death and years o

life lived with disabilities by survivors with such health

problem, weighted by the severity of the disability.

Quality of life (physical, mental, emotional and

spiritual) could be measured by Quality Adjusted Life

Years (QALYs).


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Fertility Statistics

The following indicators are used inmeasurement of fertility in the community.Those indicators are used also to evaluatethe effectiveness (impact) of family planningprogram. Fertility indicators include:

1. Crude Birth Rate (CBR)

2. General Fertility Rate (GFR) 3. Fecundity Rate (FR)

4. Age Specific Fertility Rate (ASFR)

5. Total Fertility Rate (TFR)


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Fertility Statistics

For the first three indicators: The sources of

data are the vital statistics on births and

demographic data on total population andnumber of females in the reproductive age.

Those data are collected from health offices

all over the country.

For the other two indicators: The sources ofdata are community-based surveys


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1-Crude Birth Rate (CBR):

Crude Birth Rate is the number of live births per 1000population in certain year and locality.

CBR=Number of LBs in a certain year and locality X1000Mid Year Population in the same year and locality

The CBR in Egypt year 2004 is 25.8 per thousand

populations.

CBR, as most annual rates, relates demographic

events to the population at midyear (the population inJuly 1st.), which is considered to be the average

population at risk during the year.


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2-General Fertility Rate

(GFR): GFR is the number of live births per 1000

females aged 15-49 years in a given year and

locality.

G FR = No. of live births in a certain year and locality X 1000No. of females aged 15-49 years in the same year and locality


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2-General Fertility Rate GFR in Egypt year 2005 is 108 births /1000

females in the child bearing age. The GFR is much more indicative of changes in

fertility than is the crude birth rate because it relatesbirths more nearly to the age-sex group at-risk of

giving birth (i.e. women 15-49 years of age). Thiseliminates distortions that might arise because ofdifferent age and sex distribution in a total population.

Egypt 2005 data showed that Females in the

Reproductive Age constitute 25% of the totalpopulation. The GFR is estimated to be 4 times theCBR

GFR does not consider whether those females are

married or not.


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Fecundity Rate (FR):

FR = No. of LBs in a certain year and locality X 1000No. of married WRA in the sameyear and locality

Studies in Egypt showed that MWRA

constitute 16.7% of the total population

(about one sixth of the population). The

FR is estimated to be 6 times the CBR


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Fecundity rate is a more sensitive fertilityindicator than the GFR, because it relatesbirths to Married Women in the Reproductive

Age (MWRA).

Both the GFR and FR do not consider thefertility capacity within the reproductive period(15-49 years of age). Young women havehigher fertility capacity than the very youngand the older women within the reproductiveperiod

Fecundity Rate (FR):


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4- Age Specific Fertility

Rate (ASFR):

ASFR is the number of live births to women in

specific age interval (usually 5 years) per

1000 females in the same age interval, in acertain year and locality

Example: ASFR for women aged 20-24 =No. LBs to WRA 20-24 years in a certain year and locality X 1000

Number of females aged 20-24 years in the same year and locality


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Age Specific Fertility

ASFR is more sensitive indicator for measurementof fertility for the females in the different agegroups within the reproductive period.

ASFR is used to calculate the Total Fertility Rate.

Data derived from the Demographic and HealthSurvey provides information about ASFR.

ASFR identify the specific age group, who needs

more efforts for family planning program. ASFR assess the magnitude of the problem of at-

risk pregnancies (Teen age and after 35 years oldASFR).


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5- Total Fertility Rate (TFR):

TFR is the average number of children thatwould born alive to a woman during herreproductive life, if she pass through all herchildbearing years, conforming to the age-

specific fertility rates ofa given year. For comparison between countries, TFR is

used because it is standardized for age andthe age structure of the individual countries.

Calculation of TFR: TFR could also becalculated by multiplying the ASFR for eachgroup (5-year age group) by 5, then addingthe seven group together (see the table 4.1).


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Table (4.1) Age Specific Fertility Rates (ASFR) and

Total Fertility Rates (TFR) in Egypt, 2005 (EDHS

2005).

TFR, 2005 ASFR, 2005 Age Groups

240 48 15-19

875 175 20-24

970 194 25-29

625 125 30-34

315 63 35-39

95 19 40-4410 2 45-49

3130 Total fertility / 1000 Women

3.1 Total Fertility/Woman


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