Public Health recap

Question 1

Incidence

Answer 1

number of new cases of a disease/ condition in a population per unit time (usually per year)

Question 2

Prevalence

Answer 2

number of existing cases of a disease/ condition in a population at a given point in time

Question 3

What is meant by primary prevention

Answer 3

Aims to prevent the onset of disease and involves interventions that are applied before any evidence of disease is present

Question 4

What is secondary prevention

Answer 4

Detection of disease in earliest stages before symptoms are present and intervening to slow, stop or reverse disease progression

Question 5

What is tertiary prevention

Answer 5

Interventions designed to arrest the progress of established disease and minimise its negative consequences.

Question 6

What is bias

Answer 6

a systematic deviation from the true estimation of the association between exposure and outcome

Question 7

What is selection bias

Answer 7

Systematic error in selection/allocation of study participants

Question 8

What is information bias

Answer 8

Systematic error in measurement/classification of exposure or outcome

Question 9

**What is screening

Answer 9

A process which identifies apparently well individuals who may be at increased risk of developing a condition in the early stages of a condition so that intervention can alter the disease course → reduce morbidity and mortality

Question 10

Examples of screening programs

Answer 10

Bowel (60-74)
Breast (50-70, soon to become 47-73)
Cervical cancer (over 25s)
AAA (men >65)
Fetal anomaly screening programme (FASP at 20 weeks)
Diabetic eye screening (yearly)
Newborn and infant physical examination (NIPE within 72 hours birth)
Newborn heel prick test (at 5 days)

Question 11

Principles of screening

Answer 11

Important condition
Population for screening identified
Cost effective
Natural history of disease must be known
Early/latent stage recognisable
Suitable test (safe, acceptable to public, appropriate for condition)
Effective and acceptable treatment
Continuous process, not one off event

Question 12

What is True Positive

Answer 12

Result is positive and they actually have the disease

Question 13

What is True Negative

Answer 13

Result is negative and they do NOT have disease

Question 14

What is False positive

Answer 14

Result is positive but they do not have the disease

Question 15

What is False negative

Answer 15

Result is negative but they do have the disease

Question 16

Sensitivity

Answer 16

Ability of a test to correctly identify those with the disease.

Question 17

Specificity

Answer 17

Ability of test to correctly exclude those who don’t have the disease

Question 18

PPV

Answer 18

proportion of the positive results that are true positives

Question 19

NPV

Answer 19

proportion of the negative results that are true negatives

Question 20

Limitations of screening

Answer 20

False positives - unnecessary stress to those who dont have the disease
Negative results mean people feel they have a license to take risks
Over detection of sub-clinical cases
‘Harm” from screening e.g. radiation exposure in mammography

Question 21

Limitations of using PSA as a screening test for prostate cancer

Answer 21

Not very specific to prostate ca as it can be elevated by a number of conditions
eg: prostatis

Question 22

Limitation of using D-dimer to detect pulmonary embolism? Is is a sensitive/specific test?

Answer 22

D-dimer is very sensitive but not very specific

Therefore it picks up PE if it’s there but can be elevated due to a number of conditions including pregnancy

Question 23

What is absolute risk, give example

Answer 23

Risk of developing a disease (eg: lung cancer) over a time period
Eg: risk of lung cancer is 45/ 300 in smokers and 5/700 in non smokers

Question 24

What is relative risk, give example

Answer 24

Risk of getting a disease (eg: lung cancer) in exposed group (eg: smokers) compared to an unexposed group (eg: non-smokers)
It’s a ratio so has NO UNITS
Eg: 45/300 divided by 5/700 = 21.4 x the risk of lung cancer in smokers compared to non smokers

Question 25

What is absolute risk reduction

Answer 25

Rate of disease in exposed that may be attributed to exposure.
Ie: incidence in exposed minus incidence in unexposed.
Eg: 45/300 (risk of lung cancer in smokers) – 5/700 (risk of lung cancer in non-smokers).

Question 26

How to calculate number needed to treat for one person to benefit

Answer 26

NNT = 1/ARR

round up

Question 27

Define a never event

Answer 27

a serious, largely avoidable patient safety event which should not occur if the available preventative measures have been implemented

Question 28

examples of never events

Answer 28

Wrong site surgery/ foreign object retained.
Wrong drug dose/ route.
ABO incompatibility.
Mental health: escape of transfer patient.

Question 29

Difference between error and neglect

Answer 29

Error: an unintended outcome.
Neglect: falling below the acceptable standard of care.

Question 30

Types of error

Answer 30

Errors of commission: doing something.

Errors of omission: not doing something.

Question 31

What are latent errors

Answer 31

Errors in the system

e.g. not having 2 people to check a drug chart

Question 32

What is the Swiss Cheese Model

Answer 32

Each layer represents processes which have been put in place to prevent errors happening.
Holes are where processes can fail.
When the holes in the cheese line up an error can occur.

Question 33

*Define negligence

Answer 33

Breach of legal duty of care owed which results in harm to that patient

Question 34

4 questions to determine if negligence has occured

Answer 34

Was there a duty of care?
Was that duty of care breached?
Did the patient come to harm?
Was the harm due to the breach in duty of care?

Question 35

2 tests of negligence

Answer 35

Bolam: would a group of reasonable doctors have done the same?
Bolitho: would it have been reasonable of them to do so?

Question 36

Factors affecting patient compliance

Answer 36

Socioeconomic – related factors eg. long distance from treatment setting
Health system – related factors eg. supply of medication
Condition – related factors eg. memory impairment
Therapy – related factors eg. complex treatment regimens
Patient – related factors eg. disbelief/denial of diagnosis

Question 37

List as many coronary artery disease risk factors as possible

Answer 37

Increased Age
Male Gender
Family History
Smoking
Obesity
Hypertension
Hyperlipidaemia
Diabetes Mellitus
Sedentary Lifestyle
Psychosocial Wellbeing
Alcohol Consumption
Genetic Factors
Plasma Lipoprotein(a) concentration
Coagulation Factors
C-Reactive Protein
NSAIDs

Question 38

Principles of treatment of substance misuse

Answer 38

Minimise harm eg. decrease risk of blood-borne virus infection/transmission
Substitute prescribing eg. methadone or buprenorphine for opioid addiction
Psychosocial interventions
Residential treatment
Self-help groups

Question 39

*What are the 3 times you can break confidentiality?

Answer 39

If they are a risk to the public (they intend to commit a crime) - benefits to society/an individual outweigh the benefits of maintaining confidentiality
If they have given consent
If it is required by law - notifiable diseases e.g. ebola

Question 40

Examples of vaccines and their uses

Answer 40

Meningitis B vaccine (protection against meningococcal group B bacteria)
5in1 vaccine (protection against Hib bacteria)
Pneumococcal vaccine (protects against pneumococcal bacteria)
Hib/Men C (protects against Hib and Meningococcal group C bacteria)

Question 41

*Endemic

Answer 41

disease permanently present within a population in a particular geographical area and /or normal prevalence of the disease

Question 42

*Epidemic

Answer 42

an increase in the prevalence of a disease above the number usually observed in the population in a particular area

Question 43

Pandemic

Answer 43

an EPIDEMIC which occurs in several countries or continents