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Measurement of morbidity By

Dr Mona Mohammed Hassan


ď Ž

Any departure, subjective or objective, from a state of physiological well- being

Units of measurement   

Person who were ill Illness Duration of these illnesses

Morbidity aspects 

 

Frequency : for disease ( incidence & prevalence rate) Duration : disability rate Severity : the case fatality rate

The value of morbidity data 

Describe the extent and nature of diseases Provide more comprehensive and accurate information for basic researches Serve as starting point for etiological studies Needed for monitoring and evaluation of disease control activity.

Incidence The number of new cases occurring in a define population during specific period of time ď Ž Incidence rate = No of new cases of specific D during specific period of time X 1000 Population at risk during that period ď Ž

Incidence Incidence refers :  Only new cases  During a given time  Specific population ( at risk)  New spell or episodes of disease

Incidence Special incidence rate:  Attack rate  Secondary attack rate Uses: health status indicator  To control diseases  For research into etiology, pathogenesis, distribution, and efficacy of preventive& therapeutic measures

Prevalence 

Refer to all current cases (old& new) existing at a given point in time or over a period of time in specific population Types;  

Point prevalence Period prevalence

Relationship between incidence & prevalence 

Prevalence depend on 2 factors incidence and duration of illness P=IXD

Incidence is related to occurrence of the disease that means it reflect etiological factors Duration is related to factors affect the course of the disease (prognostic factors)

Uses of prevalence

ď Ž

Helps to estimate the magnitude of health

ď Ž

Useful for planning purposes

Differences between I& P incidence


Acute diseases


New cases

New & old

Short incubation period

Long duration



Cohort study

Cross sectional

Measurement of morbidity  
Measurement of morbidity