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MCQ revision > Epidemiology > Flashcards

Epidemiology Flashcards

1
Q

A quality assurance program should include all the following features EXCEPT:

a - identify who is your customer (patient)
b - identify what services are required by the customer (patient)
c - identify how services are provided to the customer (patient)
d - identify the cost of the services to the customer (patient) compared to other institutions
e - identify processes by which services to the customer (patient) may be improved

A

d - identify the cost of the services to the customer (patient) compared to other institutions

the audit cycle

Can’t find this anywhere but presume it is because an audit compares it’s own outcomes against a standard, not another institution?

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2
Q

What does random allocation achieve?

a - equal numbers in each arm of the trial
b - equal distribution of confounding factors
c - increased readership of your article
d - equal distribution of possible unknown factors

A

d - equal distribution of possible unknown factors

B is also correct BUT the point is controlling of unknown confounders

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3
Q

You perform a biophysical profile on 100 patients. The test is positive in 10 cases. There are 2 stillbirths, both of which occurred in patients with a positive test result. The sensitivity of the test is:

a - 0%
b - 2%
c - 20%
d - 80%
e - 100%
A

e - 100%

O

Sensitivity = Chance that the test result will be positive in a patient who actually has the disease

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4
Q

A rapid diagnostic test for Chlamydia trachomatis has a sensitivity of 95% and a specificity of 95%. In a sexually transmitted diseases clinic with a prevalence of chlamydial infection of 30%, the predictive value of a positive test is approximately 90%. In a private practice with chlamydia prevalence of 5%, the predictive value of a positive test would be about

a - 5%
b - 30%
c - 50%
d - 90%
e - 95%
A

c - 50%

O

PPV = (sensitivity x prevalence) / [ (sensitivity x prevalence) + ((1 – specificity) x (1 – prevalence)) ]

PPV = true positives / all positives

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5
Q

For constant levels of sensitivity and specificity, INCREASING the prevalence of the condition in the sample will:

a - decrease the PPV
b - increase the PPV
c - not alter the PPV
d - increase, or decrease the PPV, depending on other factors

A

b - increase the PPV

O

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6
Q

The statistical power of a study is most likely to be increased by

A. selecting an outcome end-point occurring at a higher frequency
B. selecting an outcome end-point occurring at a lower frequency
C. increasing the sample size
D. selecting a Beta-value if 80%
E. employing a statistician

A

C. increasing the sample size

O

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7
Q

Which of the following is an example of an indirect maternal death

a - woman dies after massive postpartum haemorrhage
b - woman dies of fatal intracerebral haemorrhage associated with an eclamptic fit
c - woman, 28 weeks, dies of pulmonary oedema secondary to mitral stenosis
d - woman who has fatal renal shutdown after a placental abruption
e - woman dies of intraabdominal haemorrhage caused by an ectopic pregnancy
f - woman dies from septicaemia after premature rupture of membranes followed by CS

A

d - woman who has fatal renal shutdown after a placental abruption

Official answer

Indirect: Resulting from previous existing disease or disease that developed in pregnancy not due to obstetric cause but aggravated by physiological effects of pregnancy

I can’t make sense of why ‘c’ isn’t true as pregnancy has exacerbated a pre-exitsing condition?

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8
Q

Bias is

a - reduced by increasing sample size
b - systematic error
c - not affected by blinding

A

b - systematic error

consistently pushes results one way

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9
Q

Most likely to cause maternal mortality

a - mitral stenosis
b - diabetes
c - PIH
d - Pulmonary stenosis

A

a- mitral stenosis

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10
Q 
In RCT the proven benefits of screening for GDM are
a - decreased PNM
b - decreased shoulder dystocia
c - decreased neonatal jaundice
d - all of the above
e - none of the above
A

d - all of the above

HAPO

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11
Q

The difference between a case-control and a cohort study is:

a - in a case-control study the subjects are allocated by disease status and in a cohort study by exposure status
b - in a case-control study the subjects are allocated by exposure status and in a cohort study by disease status
c - a case-control study is retrospective whereas a cohort study is prospective
d - a case-control study is prospective whereas a cohort study is retrospective

A

a - in a case-control study the subjects are allocated by disease status and in a cohort study by exposure status

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12
Q

Re positive predictive value. Which is correct?

a - For a given sensitivity and specificity positive predictive value increases with increasing prevalence
b - PPV may increase or decrease with increasing prevalence depending on other factors

A

a - For a given sensitivity and specificity positive predictive value increases with increasing prevalence

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13
Q

Which of the following is CORRECT?

a. The sensitivity of a test is proportional to the specificity
b. Sensitivity and specificity are properties of a test not affected by the prevalence of the disease in question
c. Sensitivity and positive predictive value are interchangeable terms
d. Specificity is the reciprocal of the negative predictive value
e. When testing for a rare disease, a test with a high sensitivity and specificity will also have a high predictive value

A

b. Sensitivity and specificity are properties of a test not affected by the prevalence of the disease in question

O

PPV and NPV are dependent on disease prevalence

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14
Q

What is a ‘placebo effect’

a. The improved outcome from an inert therapy
b. The effect of blinding patients to the nature of their therapy
c. The effect of blinding clinicians to their patients allocation
d. The effect of blinding those assessing outcomes to the allocation
e. The difference in outcomes between patients and controls

A

a. The improved outcome from an inert therapy

O

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15
Q

The perinatal mortality rate is

a. The number of babies born alive who die within 28 days of birth divided by the total number of live births
b. The sum of the stillbirth rate and the neonatal death rate
c. The number of stillbirths divided by the total number of babies born
d. The sum of the number of stillbirths and the number of neonatal deaths divided by the total number of births

A

d. The sum of the number of stillbirths and the number of neonatal deaths divided by the total number of births

O

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16
Q

In an RCT of a new repair technique for rectocele, the MOST APPOPRIATE method for determining outcome of the repair is

a. Sim speculum examination by surgeon after 3 months
b. Validated Pelvic organ prolapse questionnaire assessed by the surgeon after 3 months
c. POP-Q score by a blinded assessor at 3 months
d. Bimanual examination by a blinded external observer at 3 months

A

c. POP-Q score by a blinded assessor at 3 months

17
Q

The statistical power of a study is MOST LIKELY to be increased by

a. Increasing the sample size
b. Employing a statistician
c. Selecting a beta value of 80 percent
d. Selecting an outcome end-point occurring at low frequency
e. Selecting an outcome end-point occurring at high frequency

A

a. Increasing the sample size

18
Q

The current perinatal mortality rate (for births at least 400g or 20weeks) in Australia is CLOSEST TO

a. 5 per 1000 live births
b. 5 per 1000 total births
c. 10 per 1000 live births
d. 10 per 1000 total births
e. 15 per 1000 live births
f. 15 per 1000 total births

A

d. 10 per 1000 total births

O

Approximately 1%
TOTAL births is denominator

19
Q

100 high risk patients undergo fetal biophysical profile. 10 patients have a positive test. Two stillbirths result, both of which came from the pool of patients with a positive test. The sensitivity of the fetal biophysical profile test in this population is

a. 0 percent
b. 2 percent
c. 20 percent
d. 80 percent
e. 100 percent

A

e. 100 percent

20
Q

Which is LEAST CORRECT

a. A finding of no difference between the two arms of an RCT may reflect the fact that the study did not have a sufficient sample size to detect a clinically important difference
b. When an RCT that addresses a clinical problem has been performed, this will outweigh all other evidence
c. The incorporation of multiple trial centres facilitates the achievement of a large sample size often required for an RCT, but may necessitate flexible trial protocols to accommodate a broad spectrum of clinical opinion
d. Flexible entry criteria facilitate the achievement of a large sample size often required for an RCT but at the cost of a conclusion drawn from a heterogeneous population that may not apply to subgroups within the population.

A

b. When an RCT that addresses a clinical problem has been performed, this will outweigh all other evidence

O

21
Q

Review the diagram and choose the CORRECT statement

                         Disease present	Disease absent Test positive	                      80	                20 Test negative	                      20             	80

a. The test correctly identified 40% (80/200) of the disease in the study participants
b. The negative predictive value was 80% in this study
c. The sensitivity and specificity were each 40%
d. If the test detected serious female disease and cost $10, it would be cost effective to screen all women

A

b. The negative predictive value was 80% in this study

O

22
Q

Testing a newborn for phenylketonuria is

a. Diagnostic testing
b. Predictive testing
c. Carrier testing
d. Exclusion testing

A

a. Diagnostic testing

23
Q

Which of the following programs LOWERS total medical costs

a. Maternal serum alpha-fetoprotein screening in pregnant women
b. Screening mammograms for women aged 40-50
c. Antepartum steroids given to mothers before the premature delivery of an infant
d. Complete blood counts as part of an annual routine examination

A

c. Antepartum steroids given to mothers before the premature delivery of an infant

O

24
Q

Which one of the following is LEAST CORRECT?

A. A finding of no difference between the two arms of a Randomised Controlled Trial may reflect the fact that the study did not have a sufficient sample size to detect a clinically important difference

B. Where a Randomised Controlled Trial that addresses a clinical problem has been performed, this will outweigh all other evidence

C. The incorporation of multiple trial centres facilitates the achievement of a large sample size often required for a Randomised Controlled Trial, but may necessitate flexible trial protocols to accommodate a broad spectrum of clinical opinion

D. Flexible entry criteria facilitate the achievement of a large sample size often required for a Randomised Controlled Trial, but at the cost of a conclusion drawn from a heterogeneous population that may not apply to subgroups within the population

A

B

25
Q

What sample size would be required to have 80% power to detect a 25% decrease in poor birth outcome which is currently 4: 1000 with an error of 0.05?

a) 200
b) 0.200
c) 20,000
d) 200,000

A

c) 20,000

* CHECK as M answer says D

26
Q

A meta-analysis of the early small randomised controlled trials of low dose aspirin in pregnancy showed a significant reduction in the frequency of proteinuric preeclampsia OR 0.4 (Confidence Interval 0.3 - 0.86).
Which of the following statements would be INCOMPATIBLE with this result?

a. Low dose aspirin is effective in preventing proteinuric preeclampsia.
b. Increasing the sample size would necessarily strengthen the findings.
c. The result could have been due to chance.
d. The result is consistent with an odds reduction of between 14% and 70%.
e. Unpublished trials would be likely to show a smaller effect.

A

b. Increasing the sample size would necessarily strengthen the findings.

O

27
Q

The GOAL of disease screening is to

A. identify individuals at high risk for a particular disease state
B. identify individuals early so less expensive therapies are used in treatment
C. identify disease states prior to clinical disease manifestation for better cure rates
D. identify asymptomatic or low risk individuals testing at different intervals
E. identify individuals at future risk to eliminate later testing

A

C. identify disease states prior to clinical disease manifestation for better cure rates

O

28
Q

Which one of the following is TRUE?

A. The risk estimate from a case-control study is more reliable than from a cohort study
B. The risk estimate from a case-control and cohort studies are equally reliable
C. The risk estimates from the case-control and cohort studies are not comparable
D. The risk estimate from a case-control study is less reliable than from a cohort study

A

D. The risk estimate from a case-control study is less reliable than from a cohort study

O

29
Q

Which of the

A
30
Q

The reporting requirements for Randomised Control Trials are contained in the:

A. Cochrane Database
B. NICE standard
C. CONSORT statement
D. QUOROM checklist

A

C. CONSORT statement

O

31
Q

The central tendency and spread of biological data which is not normally distributed is appropriately described by:

A. median and interquartile range
B. logarithmic mean and percentile range
C. median and standar deviation
D. mode and outlier range

A

A. median and interquartile range

As per RANZCOG MCQs Feb 2008

32
Q

Which is the best test for a rare slowly progressive disease?

a. Case control
b. Cohort
c. RCT
d. Case series

A

a. Case control

M

33
Q

The ability of a test to detect persons with a condition?

a. Sensitivity
b. Specificity
c. Odds ratio
d. PPV

A

a. Sensitivity

M

34
Q

Number of women who will live to their 90’s if alive at 50?

a. 75%
b. 50%
c. 10%
d. 5%

A

c. 10%

M

*review

35
Q

How many women die every day world wide because of a pregnancy related problem?

a. 100
b. 700
c. 1400
d. 3600

A

c. 1400

M

I think b 700 - WHO quotes 800 in 2017

36
Q

A markedly increasing population growth in some third world countries is chiefly related to

a. Reduced death rate
b. Social and cultural changes
c. Increase in birth rate
d. Failure of contraception
e. Improvements in obstetric care

A

a. Reduced death rate

M

*review

37
Q

Which of the following statements is LEAST correct?

A. The perinatal mortality rate in Australia and New Zealand is approximately 8/1000
B. The perinatal mortality rate in Papa New Guinea is approximately 20/1000
C. The maternal mortality rate in Australia and New Zealand is approximately 1/10,000
D. The maternal mortality rate in Papa New Guinea is approximately 1/250
E. There are approximately 1500 maternal deaths world-wide each day

A

B. The perinatal mortality rate in Papa New Guinea is approximately 20/1000

O

?source

MCQ revision (21 decks)

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