This document discusses various epidemiological terms used to measure disease occurrence and health indicators in a population. It defines rates, ratios, proportions and compares their uses. Specific terms defined include crude death rate, specific death rate, case fatality rate, proportional mortality rate, prevalence, incidence, attack rates and standardized death rates. Factors that can impact prevalence and incidence over time are also outlined.

1. PRESENTED BY,
MR. KAILASH NAGAR
ASSIST. PROF.
DEPT. OF COMMUNITY HEALTH NSG.
DINSHA PATEL COLLEGE OF NURSING, NADIAD

2.  Mortality.
 Morbidity.
 Disability.
 Presence & absence or distribution of..
 Medical needs.
 Utilization of health services.
 Demographic variables.

3. Rate
Ratio
Proportion

4.  Measures the occurrence of an event or
disease in a given population during a given
period (one Year).
(Birth rate, growth rate, accident rate)
 Usually expressed per 100 or per1000
population.
 It has a time dimension, whereas a
PROPORTION does not.

5.  A fraction is made up of 2 numbers.
 The top number is called the
NUMERATOR
 and the bottom number is called the
DENOMINATOR.
 In the fraction ¾ the 3 is the numerator
and the 4 is the denominator.

6. No of death in one year
•  Death
rate= -------------------- X 1000
• Total mid year population
•Numerator
Denominator.
Time
specification
Multiplier
• (Numerator is part of denominator )

7.  The value obtained by dividing one
quantity by another- X/Y.
 Male to female ratio.
 A ratio often compares two rates,
death rates for women and men at a
given age.

8.  Ratio also expresses relation of size
between the two quantities.
 Numerator is not part of Denominator.
 Expressed as X / Y.
Doctor : Population ratio.
Male : Female ratio.
WBC : RBC ratio

9.  A part/share or number considered in
comparative relation to a whole.
 "the proportion of greenhouse gases
in the atmosphere is rising”
 Usually expressed as a percentage %

10.  This is also relation /magnitude between
two quantities, And numerator is always
part of denominator.
 And expressed as percentage
-Proportion of female students .
-Proportion of anemic mothers
(60% mothers are anemic)

12. Incidence
Occurrence of new cases
•
Prevalence
Existence of all new & old cases.

13.  Prevalence:- how many people in
a population currently have the
disease (Photograph)
 Incidence:- how many people are
diagnosed each year (Film)

14. Cure rate

15. New cases

16. • The rate at which acute
disease is spreading --
used during epidemics
& expressed in %.
Attack rate
• % of exposed persons
developing disease after
primary case exposure
Secondary
attack rate

17. •Prevalence at any
given point of time.
• 4% TB cases on 1st April
Point
prevalence
•Prevalence at a given
period of time.
•Period will be 1year.
Period
prevalence

18.  Longer duration of the disease.
 Prolongation of life, with treatment.
 If incidence increases.
 Immigration of new cases.
 Better reporting of cases.


19. Longer
duration of
disease
Incidence
increases.
Prolongation
of life
without
cure.
20

20.  Shorter duration of diseases.
 Improved cure rate.
 Incidence decreases.
 Emigration of new cases.
 Under reporting of cases.

21. Improved cure rate.
Short duration of
disease.
Incidence decreases

23.  Crude Death Rate.
 Specific death rate.
 Case fatality rate.
 Proportional mortality rate.
 Survival rate.
 Standardized death rate.

24.  Number of deaths from all causes, per 1000
estimated mid year population in one year in
a given place.
No deaths during one year
CDR = X 1000
Mid year population

25.  Cause Specific death ratelike
disease death rate, Road accident…
 Age specific-IMR, Child Mortality rate
 Sex specific death rate – MMR/female
 Period specific death rate–Death in May

26.  Percentage of particular cases dying
during particular disease epidemic.
 Killing power of disease particularly
acute diseases
No of deaths due to cholera
 CFR= ----------------------- X 100
Total No of cholera cases

27.  Proportion or % of deaths due to particular
cause out of total deaths.
 It measures the disease burden.
 Under 5,
proportional =
mortality rate
No of deaths below 5 years
-------------------- X 100
Total No all of deaths

28.  Percentage of the treated patients remaining
alive at the end of 5 years treatment.
 Yard stick for assessing the standard of
therapy in cancer.

Sur
vival
Rate
pts alive at the end of 5 yrs
= ---------------------- X 100
Total No of pts treated

29.  CDR can not be useful for comparison.
 Death rate need to be standardized
for comparisons.
 Standardization can be done by-
:adjusting death rate age wise,
:also can be done sex/race wise