Health Measures (Sept 6)

Question 1

PICOT

Answer 1

successful framework to form research question

Question 2

P (PICOT)

Answer 2

Population: demographics (age, sex, race)

Question 3

I (PICOT)

Answer 3

Intervention: what are we going to do/change (drug, food, behaviour)

Question 4

I (PICOT) in Observational study

Answer 4

Exposure- what people choose to do in their everyday lives

Question 5

C (PICOT)

Answer 5

Comparator: other group that we compare to (drug, placebo, or nothing)

Question 6

O (PICOT)

Answer 6

Outcome: effects that are wanted or unwanted

Question 7

T (PICOT)

Answer 7

Time: over how long

Question 8

What kind of research question is this and identify all parts of PICOT:

In black female undergraduate students, does regular consumption of 3 glasses of milk/day compared with no milk result in higher bone density at age 40

Answer 8

Population: black female undergraduate students

Intervention: does regular consumption of 3 glasses of milk/day

Comparator: compared with no milk (standard of care or placebo)

Outcome: result in higher bone density

Time: at age 40

-preventative research question (I is preventative measure)

Question 9

In patients with rheumatoid arthritis is glucosamine sulphate more effective than placebo at relieving self-reported morning “wake up” pain?

Identify type of research question and parts of the question

Answer 9

P: in patients with rhematoid arthritis

I: glucosamine sulphate

C: placebo

O: relieving self-reported morning “wake up” pain

-therapy/treatment question

Question 10

For deep vein thrombosis is D-dimer testing or ultrasound more accurate for diagnosis

Identify parts of research question and type

Answer 10

P: deep vein thrombosis

I: D-dimer testing

C: ultrasound (standard of care- old reference test)

O: more accurate for diagnosis (false +, false -, etc.)

-diagnosis research question

Question 11

In women with ER- breast cancer within 1 year of diagnosis, what is the survival rate?

Identify what type of research question this is and its parts

Answer 11

P: women with ER- breast cancer

I: within 1 year of diagnosis

O: what is the survival rate

no comparator

-prognosis question

Question 12

Identify parts and type of reserach question:

Do adults who binge drink compared to those who do not have higher mortality rates?

Answer 12

P: adults

I: binge drinking (exposure)

C: compared to those who don’t binge drink

O: have higher mortality rates

-etiology question

Question 13

Proportions

Answer 13

[c]/[c+Non-c] -fraction with numerator included in denominator -dimensionless -values range from 0 to 1 (bounded)

Question 14

Rates

Answer 14

-measure of the frequency with which an event occurs in a defined population in a defined time -ex: number of cases of HIV/10000 Canadians/year -per unit “something” -no upper bound (can approach infinity with catastrophic event)

Question 15

Incidence Proportion (cumulative incidence) calculation

Answer 15

[Number of new cases of disease in population over a period of time]/[Number of people alive and at risk in same population at the beginning of the period]

• assumes no recurrence of event (once you have it you are no longer at risk of getting it again)
• denominator includes only people at risk for developing disease

Question 16

Estimate the incidence proportion of diabetes in a nursing home with 800 residents from Jan 1 to Dec 31 2018. On Jan 1, 50 of them already have diabetes (prevalent cases). 25 develop diabetes over the 12 months.

Answer 16

25/750=0.033 or 3.3%

Question 17

Attack rate

Answer 17

-incidence proportion in the setting of an outbreak

Question 18

Outbreak

Answer 18

-sudden increase in occurrences of a disease in a time and place

Question 19

What is the attack rate during a flu outbreak in a nursing home with 800 residents if 150 of them develop the flu during the period of the outbreak?

Answer 19

150/800=18.75%

Question 20

Vaccinations and risk of disease

Answer 20

-vaccinated individuals should still remain in denominator as “at risk for developing the disease” -vaccine is not 100% effective (could be different strain)

Question 21

Incidence Rate definition

Answer 21

• number of new cases (“incidence”) per unit time (“rate”)
• instead of persons at risk as the denominator, we use person time at risk

Question 22

Incidence Rate

Answer 22

[Number of New Cases]/[Person-time at risk]

Question 23

Person-time

Answer 23

-estimate of actual time at risk in years, months, or days that all participants contribute -participant contributes person-time if they are disease free and still at risk for developing the disease

Question 24

What is the incidence rate of diabetes if person-time of person A is 19 days, person B is 365 days, person C is 148 days, person D is 365 days, and person E is 134 days?

Answer 24

Total cases of diabetes in year: 3 Total person-days: 1031 days 3/1031=0.0029 (2.9 cases per 1000 person-days)

Question 25

Point prevalence

Answer 25

[# of people with a disease at a specified point in time]/[# of people in population at specified point in time- diseased and non-diseased]

Question 26

Determine the point prevalence of diabetes in a nursing home with 800 residents on Jan 1. On Jan 1, 50 of them already have diabetes (prevalent).

Answer 26

50/800=6.3% (point prevalence)

Question 27

Determine the point prevalence of diabetes in a nursing home with 800 residents on Dec 31 2018. On Jan 1 2018, 50 of them already have diabetes (prevalent). 25 people develop diabetes over the year.

Answer 27

75/800=9.4%

Question 28

Incidence

Answer 28

-measure of change from non-disease to disease (numerator) in a population at risk (denominator) over a specific period of time

Question 29

Incidence proportion/cumulative incidence

Answer 29

• measure of occurence of new cases during a defined span of time
• the probability of developing disease over a stated period of time
• problems: competing risks result in deaths before the observation period ends, people may leave the study, diseases can occur at any point in an interval, many diseases recur