Epidemiology Flashcards
A patient asks you about a drug she saw advertised to treat her diagnosis. A recent journal article studied to treat her diagnosis. A recent journal article studied the drug’s effect and reported Number Needed to Treat (NNT) of 24. You tell your patient:
- 24 patients in the trial benefited from the drug
- You have 24% change of benefiting from the drug
- 24 individuals with characteristics like those in the trial would need to be treated with this drug for one individual to benefit
- The absolute risk reduction is smaller compared to the relative risk reduction
- 24 individuals with characteristics like those in the trial would need to be treated with this drug for one individual to benefit
Lower the NNT, the more effective the drug
A randomized controlled trial is conducted to compare a new drug to placebo in preventing a clinical outcome (progression of a disease). The results are as follows: relative risk of disease progression on the drug is 0.80; 95% confidence interval 0.65-0.98. Your conclusion is:
- The result is significant, demonstrating that the drug is effective
- This drug is completely ineffective
- You cannot determine the effectiveness without a number needed to treat (NNT)
- The confidence interval to too broad to be useful
- The result is significant, demonstrating that the drug is effective
0.80 is the relative risk, it’s a ratio, if it’s < 1 it means the risk is less for that treatment group
if the number was 1 it means there is no effective
Always want this number to be on either side of 1
Range of possible values of the risk 0.65-0.98 you do not want the interval to cross 1 that means the
treatment had no impact. If it contains is = 1 it is not statistically significant
Rank the following trial types from most robust to least robust for clinical use:
a. Meta analysis
b. Case report
c. Randomized controlled trial
d. Cohort study
C, A, D, B or A, C, D, B
A test with high sensitivity may:
- Have a high false positive rate
- Detect 99% of individuals with the condition
- Have a high false negative rate
- Have a low specificity
- Have a high false positive rate
- Detect 99% of individuals with the condition
- Have a low specificity
Treating postmenopausal women with estrogen plus progestin will:
a. Decrease the risk of coronary artery disease
b. Decrease the risk of a bone fracture
c. Decrease the risk of blood clot
d. Decrease the risk of breast cancer
b. Decrease the risk of a bone fracture
A, C, D all increase risk
Which of the following is NOT TRUE about valacyclovir?
a. It is indicated to treat genital herpes simplex outbreak (HSV-2 outbreaks)
b. It is indicated to decrease the risk of HSV-2 transmission from an affected person to an unaffected person
c. It is indicated for treatment of seronegative people (without HSV-2 antibodies) to prevent HSV-2 infection
d. Is reliably prevents all HSV-2 transmission when used as indicated
c. It is indicated for treatment of seronegative people (without HSV-2 antibodies) to prevent HSV-2 infection
d. Is reliably prevents all HSV-2 transmission when used as indicated
Evaluation to lower the risk of death from cancer may involve which of the following:
a. Screening for early cancer
b. Screening for precancerous lesions
c. Screening for genetic predisposition to cancer (only for high risk individual)
d. Assessing cancer risk factors
All options
Which of the following is true regarding cancer screening?
a. As cancer risk increases in a population, the likelihood that an abnormal finding one exam or testing is due to cancer increases
b. A positive screening test can be used to confirm a cancer diagnosis
c. Discussion around screening should stay focused on testing and not cover cancer prevention strategies
a. As cancer risk increases in a population, the likelihood that an abnormal finding one exam or testing is due to cancer increases
Which of the following is true for a cancer with lead time bias?
a. Early diagnosis is generally effective at decreasing mortality
b. Delayed diagnosis is unlikely to have much impact on the long term outcome
c. Sensitive screening tools exist
d. Slow-growing
b. Delayed diagnosis is unlikely to have much impact on the long term outcome
c. Sensitive screening tools exist
Which of the following is true for a cancer with length time bias?
a. Early diagnosis is generally effective at decreasing mortality
b. Delayed diagnosis is unlikely to have much impact on long term outcome
c. Sensitive screening tools exist
d. Slow-growing
b. Delayed diagnosis is unlikely to have much impact on long term outcome
c. Sensitive screening tools exist
d. Slow-growing
A 45 year old female asks her PCP about breast cancer screening
during a routine physical.
Medical history: High cholesterol
Medications: Simvastatin, calcium
Family history: Mother alive, age 75, breast CA Dx age 65 and treated, father alive, age 78, CAD (s/p MI), sister
and well age 48
Social History: no smoking; 2 glasses of wine per day; no drug use, married to male partner, 2 kids ages 18 and 15
Which of the following factors does not increase her risk of breast cancer?
a. Increasing age
b. Family history of breast cancer
c. Alcohol consumption
d. Childbirth before age 30
d. Childbirth before age 30
A 45 year old female asks her PCP about breast cancer screening
during a routine physical.
Medical history: High cholesterol
Medications: Simvastatin, calcium
Family history: Mother alive, age 75, breast CA Dx age 65 and treated, father alive, age 78, CAD (s/p MI), sister
and well age 48
Social History: no smoking; 2 glasses of wine per day; no drug use, married to male partner, 2
kids ages 18 and 15
You tell her:
a. At her age, mammograms have repeatedly been shown to offer statistically significant
decreases in the risk for breast cancer death
b. Breast MRI is a good option for breast cancer screening
c. Genetic testing is good option for any woman concerned about breast cancer risk
d. It is important for every woman to make an individual decision based upon personal risks and
benefits
a. At her age, mammograms have repeatedly been shown to offer statistically significant decreases in the risk for breast cancer death
d. It is important for every woman to make an individual decision based upon personal risks and benefits
MRI’s are not generally used for an average risk patient since its very expensive, usually more used for high
risk individuals
A 45 year old female asks her PCP about breast cancer screening
during a routine physical.
Medical history: High cholesterol
Medications: Simvastatin, calcium
Family history: Mother alive, age 75, breast CA Dx age 65 and treated, father alive, age 78, CAD (s/p MI), sister
and well age 48
Social History: no smoking; 2 glasses of wine per day; no drug use, married to male partner, 2
kids ages 18 and 15
How would you advise this patient?
a. Perform breast self-exam (BSE) regularly because that is proven to increase rates of early breast
cancer detection and cure
b. There is no question that you should have annual mammography to decrease your risk of breast
cancer death with little risk of false positive
c. Consider BSE and mammography, but be aware that both have fairly high false-positive rates at your age
c. Consider BSE and mammography, but be aware that both have fairly high false-positive rates at your age
A 75 year old male is found to have an elevated PSA test on screening. Prostate exam shows moderate,
symmetrical gland enlargement. He reports waking up once or twice a night to void. Studies of prostate cancer
screening indicate:
a. PSA-detected prostate cancer death rates increase as men get older (especially above 70)
b. PSA screening for prostate cancer is a meaningful health screening in all men over age 50
c. PSA screening can detect early prostate cancer, but it is unclear whether intervening
on these PSA detected cancer will decrease overall mortality
c. PSA screening can detect early prostate cancer, but it is unclear whether intervening on these PSA detected cancer will decrease overall mortality
A 75 year old male is found to have an elevated PSA test on screening. Prostate exam shows moderate,
symmetrical gland enlargement. He reports waking up once or twice a night to void.
At this point, you should do the following:
a. Diagnose prostate cancer based upon the elevated PSA level
b. Conduct imaging studies (e.g. CT scan) and if findings are consistent with prostate cancer you can confirm the diagnosis and begin treatment
c. Obtain tissue (i.e. biopsy) before you can make a diagnosis of prostate cancer
c. Obtain tissue (i.e. biopsy) before you can make a diagnosis of prostate cancer
A 75 year old male is found to have an elevated PSA test on screening. Prostate exam shows moderate,
symmetrical gland enlargement. He reports waking up once or twice a night to void.
A prostate biopsy is performed and he is found to have prostate cancer. Additional evaluation reveals the
cancer is likely localized to the prostate gland. After an appointment with multi-disciplinary team, the patient is left
to decide between 3 options. How would you advise him?
a. Watchful waiting
b. Prostate surgery
c. Prostate radiation therapy
a. Watchful waiting
Prostate cancer is associated with which of the following:
a. Lead time bias
b. High false positive rate on screening
c. Aggressive tumors that rapidly progress to death
b. High false positive rate on screening
An 18-year-old female presents for a physical exam at her college health department. Which of the
following should be discussed regarding cervical cancer?
a. She is due for a pap test regardless of history
b. She should have a pap test only if at risk for HPV
c. Gardisil (HPV vaccination) cannot be offered to protect against HPV due to her age
d. A pap test is not indicated due to age
d. A pap test is not indicated due to age
Cervical cancer:
a. Is on the rise
b. Is often caused by a viral infection
c. Can only be detected in advanced stages
d. Is potentially vaccine preventable
e. Risk is increased with HIV infection
b. Is often caused by a viral infection
d. Is potentially vaccine preventable
e. Risk is increased with HIV infection
A 20-year-old male feels a testicular lump and presents for evaluation. What is the next step?
a. Check a PSA test
b. Remove the lump surgically
c. Perform an ultrasound for further evaluation
c. Perform an ultrasound for further evaluation
Smoking cessation counseling is provided, but the patient replies that he is too old for any impact from smoking cessation. You tell him:
a. He is right, but your clinical medicine professor suggested that you do so anyway
b. In as little as one-years time, his risk of coronary artery disease will fall by 50%
c. After stopping, his lung cancer risk wont change but at least it won’t increase as it would if he
continued to smoke
b. In as little as one-years time, his risk of coronary artery disease will fall by 50%
A 50-year-old woman presents for a physical examination. She is feeling well and takes no medications.
Family history is negative for cancers in first degree relatives. She asks about colorectal cancer screening.
Regarding colorectal screening:
a. Colonoscopy is the only currently recommended method
b. Several options are available and should be selected based upon the individual’s risk profile and preferences
c. Techniques available today can only detect cancer once it has developed
d. Has not been shown to impact mortality
e. You advise her against colorectal cancer screening
b. Several options are available and should be selected based upon the individual’s risk profile and preferences
Breast Cancer Screening Methods:
Mammogram
• MRI
• Breast exams
o Clinical breast exam (CBE)
o Breast self exam (BSE)
Confidence interval
Gives the range of expected values if the study was repeated many times, with X%
confidence (usually 95% or 99%)
o A result is significant if its confidence interval DOES NOT cross 1.0 (treatment
group/control group)
- Relative risk ratio, absolute risk ratio, odds ratio, hazard ratio
- If the value is 1, that means there is no difference between treatment and control groups,
greater than 1 increased risk
o Example: AREDS1
“Single-arm comparisons with placebo found risk reduction statistically significant for
antioxidant plus zinc…but not for the antioxidants arm (antioxidants: OR, 0.8; 99% CI,
0.59-1.09…; antioxidants plus zinc: OR, 0.75; 99% CI, 0.52-0.98)”
