Measuring Health And Disease Flashcards
Why measure the health of the population?
Find how common disease is (prevalence)
How many new cases (incidence)
Identify Longitudinal trends in disease
If intervention and policies o improve health are having an effect
Identify differences in disease patterns btw diff population groups/ locations
Organisation of service planning
Institutions for information on measuring health status
Office for national statistics
NHS digital
Uk data service
What data sources are used to measure health status
Death certificates
Census
Health survey of England
General lifestyle survey
Hospital episode statistics
GP research database
Health protection reports of notifiable infectious diseases
Cancer registration
National/ regional/ local audits or surveys
What is a death certification
Legal requirement to register death - age, sex, occupation
DRS record cause of death and contributing diseases
International classification of disease codes
What is a census
Tool for measuring population demographics
Every 10 years since 1851
Counts everyone in a household on a particular night
Age, gender, migration, education, martial status, health, housing condition, family structure, employees and travelling habits
What are hospital episode statistics
Details of all admissions to NHS hospitals in England and all outpatient appointments
Started in 1989
Secures details on:
- Diagnosis and operations
- Age, gender, ethnicity
- Time waited and date of admission
- Geographical info on where treated
- Outcome: discharge home, care home, death
What is a Clinical practice research datalink and what is it used for ?
Anonymised longitudinal data from 625 general practices serving 5 mill patients
Used for:
Clinical research planning
Studies of treatment patterns
Drug utilisation
Clinical epidemiology
Drug safety
Health outcomes
Health service planning
Types of data sources used to compile graphs
Census
Death certificate
Hospital episode statistics
Clinical practice research datalink
What is the health survey for England
- Annual population survey since 1990
- Contains questionnaire answers:
Demographic info, smoking status, self reported info on health, illness, treatment, health service usage, blood and saliva sample analysis, height and weight - Additional info on key theme each year (e.g. asthma)
- Freely available on line (via NHS digital)
What is general lifestyle survey?
Sample from whole of England
Formerly called general household survey
- Demographic info about households, families and people
- Housing tenure and household accom
- Access to vehicles
- Employment
- Education
- Health and use of health services
- Smoking and drinking
- Family info, marriage. Cohabitation and fertility
What is a “notifiable disease”?
Certain infectious disease notified by doctors
Laboratory results for some infectious diseases notified
Cancers registered in cancer registries and linked to mortality data
Key methods of measuring health and disease
Birth and fertility rates
Incidence (how many new cases)
Prevalence (how common disease is)
Mortality rate (crude and standardised)
Advantage of mortality data as a measure of population health
- Legal requirement in UK to register each death
- Little delay in collection of data
- International classification of disease ensures comparability
- Cheap source of health data
Disadvantage of mortality data as a measure of population health
- Potential for error (diagnosis/ coding/ processing/ interpretation)
- Death may result from many diseases acting in conjunction
- Some diseases have high mortality rate & death occurs quickly/ some are long term, resource-intensive but rarely cause death
How might we use mortality or mortality rates
Compare areas
- identify areas of poor health
- identify need for preventative services
- may raise hypothesis about cause of disease
Look at change over time
What is direct standardisation
Direct: age specific death rates from a study population are applied to a standard population structure
Apply standard specific death rates to other populations
Advantages of direct standardisation
- Can be used to compare disease rates across areas and time
- Can be used to assess the relative burden of different diseases in a population
Disadvantages of direct standardisation
Requires age specific rates which not always available at a local level
Rates may not be stable for a small number of events
What is indirect standardisation
Age specific rates from a standard population are applied to a study population structure (standardised mortality ratio)
What is SMR
Standardised mortality ratio
Observed no. Of deaths for study pop/ expected no. Of deaths for study population
E.g. SMR of 150% or 1.5 means study population has .5 times as many deaths as you would expect
Advantages of indirect standardisation
Doesn’t require local rates, only absolute number of events
Easier to interpret rates (always comparing to 1 or 100)
Disadvantages of indirect standardisation
Areas cannot be directly compared
Doesn’t give an idea of actual burden of disease
Pitfalls in interpreting health and disease
- Different criteria used to define the disease btw areas
- Not all cases of disease have been identified in each area
- Use of hospital data to describe disease or death in an area (omits people treated in GP or die in community)
How socioeconomic deprivation relates to bad health
People living in areas with the highest socio-economic deprivation
- Lowest life expectancy at birth
- Highest death rates from most conditions (cardio, cancer)
- Higher rates of teenage pregnancy
- Higher levels of unhealthy lifestyle (smoking, diet, physical activity)
