incidence & prevalence. definition, methods of collecting morbidity statistics. indicators. international disease classification

Question 1

define prevalence

Answer 1

number of cases divided by the population at risk

• measured using cross-sectional studies
• shows a snapshot of the disease distribution in a population at a given moment
• depends on

1. Incidence
2. Virulence
3. Treatment
4. Prevention

prevalence = (alll cases old & new)/ pop at riscl) x 10

Question 2

what is incidence (I)

Answer 2

incidence is a measure of the freq with which new cases of an illness occur in a pop over a period of time.

• used to estimate the risk of an event in a stated period of time

incidence = (new cases/pop at risk) x time x 10

Question 3

importance of prevalence and incidence

Answer 3

they provide information about ongoing processes

low prevalence= good rx. low incidence = good prevention

• ↑prevelance & ↑ incidence
  
  • epidemic, low health prevention & poor treatment
• ↑prevelance and ↓ incidence
  
  • Good prevention & poor treatment = old population w/ chronic diseases
• ↓ prevelance ↑ incidence
  
  • low prevention but good treatment
  • infectious disease w/ high fatality
• ↓ prevelance ↓ incidence
• good healthcare services w/ effective prevention and treatement

Question 4

what are the methods of collecting morbidity statistics

Answer 4

Active methods( active data collection using the following methods)

• regular checkups aka general reporting
• special reporting i.e for dangerous infections
• application of sociological methodss i.e. gather info from patients and patient’s family

Passive methods (initiative to seek medical care is left to the patient)

• data from medical and prophylactic exams
• data from causes of death

Question 5

Define the ICD

Answer 5

A system developed collaboratively between the world health organisation and 10 international centers so that the medical terms reported by physicians, medical examiners and coroners on death certificates can be grouped together for statistical purposes

revised every 10 years

includes:​

• coding rules for cause of death
• standard definitions(birth rate, death rate, etc)
• prescribes the format of death certificates
• regulates compilation and publication of statistics on disease and cause of death

current version is 11 which has 24 chapters

01 Certain infectious or parasitic diseases

02 Neoplasms

03 Diseases of the blood or blood-forming organs

04 Diseases of the immune system

05 Endocrine, nutritional or metabolic diseases

06 Mental, behavioural or neurodevelopmental disorders

07 Sleep-wake disorders

08 Diseases of the nervous system

09 Diseases of the visual system

10 Diseases of the ear or mastoid process

11 Diseases of the circulatory system

12 Diseases of the respiratory system

13 Diseases of the digestive system

14 Diseases of the skin

15 Diseases of the musculoskeletal system or connective tissue

16 Diseases of the genitourinary system

17 Conditions related to sexual health

18 Pregnancy, childbirth or the puerperium

19 Certain conditions originating in the perinatal period

20 Developmental anomalies

21 Symptoms, signs or clinical findings, not elsewhere classified

22 Injury, poisoning or certain other consequences of external causes

23 External causes of morbidity or mortality

24 Factors influencing health status or contact with health services

Question 6

what is the International Classificatinon of Diseases

Answer 6

principal means of classifying and codind morbidity and mortality

introduced in 2008

version 11 presented at World Health Assembly 2019

purpose of ICD

• includes coding rules for causes of death which allow the coder to ID the single condition/ cause of death on a death certificate that’s considered the most informative from a public health point of view
• standardises definitions e.g. ‘live death’ ‘cause of death’ ‘maternal death’
• contains tabulation lists that reccomend cause of death groupings that countries should use in order for countries to compare mortality data
• Prescribes the format of the medical certificate of death
• includes regulations regarding the compilation and publication of statistics on diseases and causes of death which require member states to use the ICD for compiling mortality and morbidity statistics

Question 7

what is the Attack rate?

Answer 7

a variant of the incidence applied to a narrowly defined population during a specific period of time (epidemic) expressed as a percentage

secondary attack rate

refers to the incidence of disease among contacts of known cases also expressed as a percentage in a specific period of time

usees

1. measure spread of infectio in family
2. determines if a disease of unknoen etio is infections
3. evulates effectiveness of control measures

case fatality ratio

the number of deaths due to diseas in a given time period among all cases of disease in the same period

Question 8

what is the secondary attack rate

Answer 8

refers to the incidence of disease among contacrs of known cases also expressed as a percentage in a specific period of time

Question 9

what’s the case fatality ratio

Answer 9

the number of deaths due to diseas in a given time period among all cases of disease in the same period

Question 10

ice berg effect

Answer 10

only a certain number of people with a disease present with the healtcare services so the statistics are skewed