1. Mortality Indicators and Morbidity Indicators
Dr. MUSTAQUE AHMED
MBBS,MD(COMM MEDICINE),FELLOWSHIP

2. Objective of the class Enumerate various mortality indicators
Describe some important mortality indicators.
To describe the morbidity measurement
To understand the incidence and prevalence
Uses of morbidity data.

3. Mortality is a term which means “death” or describes death and related issues
MORTALITY RATES
1. CRUDE DEATH RATE
2. SPECIFIC DEATH RATE
3. CASE FATALITY RATE
4. PROPORTIONAL MORTALITY RATE
5. SURVIVAL RATE
6. ADJUSTED (OR) STANDARDIZED RATES

4. CRUDE RATE
1. Crude Death Rate(CDR)- Annual number of deaths per mid year population.

5. SDR TB = NO OF DEATHS FROM TB IN YEAR X 1000
Specific Death Rates
used especially when we have to throw light on etiology
Specific to a cause eg: specific deaths due to tuberculosis ,,,HIV/AIDS
SDR TB = NO OF DEATHS FROM TB IN YEAR X 1000
MID YEAR POPULATION

6. PROPORTIONAL MORTALITY RATE
1.PMR expresses the no. Of deaths due to a particular cause per 100 total deaths.
Note : PMR is computed usually for a communicable diseases & for specific disease of major public health importance ex:cancer,CAD

7. Case Fatality Rate CFR = TOTAL NO.OF DEATHS DUE TO DISEASE X 100
Represents Killing power of a disease (how fatal a diseases can be )
It is a ratio of deaths to cases
Used For acute cases.
Expressed in percent.
Cannot be used for chronic diseases
CFR = TOTAL NO.OF DEATHS DUE TO DISEASE X 100
NO OF CASES DUE TO SAME DISEASE

8. Survival rate Expressed in percent.
Method of describing prognosis in certain disease conditions
Can be used as a yard stick for the assessment of standards of therapy
Specially useful in cancer studies
Expressed in percent.
total no. of patients alive after
5 years
= ─────────────────────× 100
total no. of patients diagnosed or
treated

9. Adjusted or standardized rates
To compare the death rates of two populations with different age- composition
Most common method of adjustment are
Direct standardization
Indirect standardization
For standardizing we need to have a standard population whose age and sex composition is known. Standard population is defined as one for which the numbers in each age & sex groups are known. National population is usually taken as standard population
Direct standardization is used whenever stable stratum-specific rates are available
Indirect standardization is used when stratum-specific rates are unavailable or unstable because of small numbers

10. Direct standardization
A standard population is chosen where the numbers of each age and sex group are known.
Apply to the standard population, the age-specific rates of the population whose crude death rate is to be adjusted
For each age group, an expected no. of deaths in the standard population is obtained
These are added together for all the age groups, to give the total expected deaths

11. Specific death rates/1000 by age for a city X
Expected deaths and standardized death rate

12. Indirect standardization
The specific death rates of the standard population are applied to the respective age groups of the populations of the areas to be compared
Standardized mortality rate is standardized for age

13. Measurement of Morbidity
It is defined as any departure, subjective or objective, form a state of physiological well being
It is known by different names like illness, sickness.
Morbidity could be measured in terms of
- persons who were ill (frequency)
- illnesses that these person experienced (severity)
- Duration of these illness (duration)
Disease frequency is measured by incidence and prevalence
Duration of illness is measured by the disability rate
Severity is measured by the case fatality rate

14. Morbidity rates for assessment of ill-health
Incidence and prevalence.
Notification rates.
Attendance rates at OP depts.
Admission, readmission & discharge rates
Duration of stay in hospital.
Spells of sickness or absence from work or school.

15. INCIDENCE
Def: Number of NEW cases occurring in a defined population during a specified period of time.
An incidence rate includes three important elements:
1. a numerator -- the number of new cases
2. a denominator -- the population at risk
3. time -- the period during which the cases occurred.
no. of new cases of specific disease
during a given time period
INCIDENCE = X population at risk during that period

16. Special incidence rates
Attack rate- it is used only when population is exposed to risk for a limited period of time such as during an epidemic
No. of new cases of a specified disease during a specified time interval
───────────────────── ─ × 100
Total population at risk during the same interval
Reflects the extent of epidemic. Expressed in percent.
Secondary attack rate-
No. of exposed persons developing the disease within the range of the incubation period
──────────────── ─ ×100
Total no. of exposed contacts
Useful in epidemiology of communicable diseases.

17. PREVALENCE
All current cases (NEW+ OLD) existing at a given point or period of time in a given population.
Obtained from cross-sectional studies.
Prevalence is two types:
point prevalence
period prevalence

19. Factors influencing prevalence
Increased by: Decreased by:
- longer duration - shorter duration
- prolongation of life - high case-fatality
- increase in new cases - decrease in new cases
- out-migration of healthy - in-migration of healthy I I
Baseline
Prevalence
Pot
Prevalence=IncidenceXDuration
Discuss using TB

20. Calculation of Incidence and prevalence

21. Relationship between incidence and prevalence
Prevalence(P) = incidence(I)×mean duration(D)
The longer the duration of the disease, greater is its prevalence
If the disease is acute, then prevalence will be low compared with the incidence

22. Uses of prevalence Uses of incidence
To estimate the magnitude of health / disease problems in the community.
Useful for administrative and planning purposes e.g. hospital beds, manpower needs.
Uses of incidence
control of disease
For research into etiology and pathogenesis, distribution of diseases.
Efficacy of preventive and therapeutic measures
Uses of morbidity data
Describe the extent and nature of the disease load in the community.