Epidemiolgy Standardisation

Question 1

How would you calculate a crude population mortality rate

Answer 1

Total deaths/ total population per 1000

Question 2

Why do you need standardisation for mortality rates?

Answer 2

As different population structures will show mortality differently e.g elderly population will show a very high disproprotionate mortality rate vs a young population

Question 3

What is direct standardisation?

Answer 3

Using the age specific death rates and then applying them to a standard population to make a new death rate. Usually compare to WHO standard population represented per 100 000

Question 4

What is the equation for calculating expected deaths in a population using direct standardisation?

Answer 4

Sum of (age specific death rate x standard population age bracket)/ 100 000

Question 5

What is the benefit of using direct standardisation?

Answer 5

Less bias, good at comparing 2 or more groups with different age distributions

Question 6

What is the equation for calculating expected deaths in a population using indirect standardisation?

Answer 6

Sum of (age specific death rate x study population age brackets)/100 000

Question 7

What is the benefit of using indirect standardisation to calculate expected deaths

Answer 7

Can look at the number of expected deaths estimating if both study and real population had the same age specific death rates but kept their real age structure.

Question 8

How do you calculate the standardised mortality ratio?

Answer 8

Observed deaths (in actual study population)/ expected deaths (as per indirect standardisation)

Question 9

What does a standardised mortality ratio <1 signify?

Answer 9

The study population has a lower than expected deaths