6 - Risk

Question 1

risk

Answer 1

the probability of the occurrence of a future adverse event in a specified time interval

Question 2

absolute risk

Answer 2

incidence of the disease in a given population or sub-population

Question 3

Attributable risk

Answer 3

proportion of disease risk in an exposed group that can be attributed to the exposure
= (incidence in exposed - incidence in not exposed) / incidence in exposed

Question 4

relative risk

Answer 4

if the relative risk <1, then it has a productive effect
for 2 groups = risk in group 1 / risk in group 2
cohort studies = risk in exposed / risk in not exposed

Question 5

Relative risk: confidence intervals

Answer 5

95% confidence interval for the log relative risk
(log RR - 1.96 x se(logRR) , log RR + 1.96 x se(logRR) ,
to get the confidence of the RR, use the exponential function

Question 6

standard error of relative risk

Answer 6

SE(RR) = square root [(1/a +1-b) - (1/c+1/d)]

Question 7

confidence intervals

Answer 7

intervals
- includes 1 = not statistically different

• does not include 1 and is always less = reduction in risk in exposed group
• does not include 1 and is always greater = increase in risk in the exposed group

Question 8

Odds and odds ratio

Answer 8

The ratio of probability of an event occurring to the probability of the event not occurring that is p divided by (1-p) where p=probability
The amount by which the odds are multiplied for one group compared with another.

Question 9

years of life lost (YLL)

Answer 9

How many years are lost (from expected lifespan) due to premature death.

Question 10

impairment

Answer 10

any loss or abnormality of psychological,

physiological or anatomical structure or function

Question 11

disability

Answer 11

any restriction or lack (resulting from an impairment) of ability to perform an activity in the manner or within the range considered normal for a human being

Question 12

handicap

Answer 12

a disadvantage for a given individual, resulting from an impairment or a disability, that limits or prevents the fulfilment of a role that is normal for that individual.

Question 13

Years Lived with Disability (YLD)

Answer 13

– Accounts for duration and severity of illness
= I x DW x L 
I = number of incidence cases
DW = disability weight
L = average duration of disability

Question 14

Disability Adjusted Life Year (DALY)

Answer 14

– Accounts for years lived with health impairment and premature death
– Lost years of healthy life
= YLL + YLD

Question 15

Quality Adjusted Life year (QALY)

Answer 15

– Inverse of DALY measure
– Years of life, adjusted to account for health impairment

– Created to allow cost-benefit analysis for interventions

Question 16

DALY vs QALY

Answer 16

DALY
• Measure health loss
• Used to assess burden of disease
• Cost-benefit of interventions – DALYs averted
QALY
• Measure health gain
• Cost-benefit analysis for interventions
• Comparison of different interventions– QALYs gained