Research/Stats/Ethics

Question 1

Sensitivity

Answer 1

• Good screeNing test but can have false positives
• Negative results are really reliable, positive results are not as reliable
• seNsitivity have reliable Negatives (CAN RULE OUT DISEASE!)
• Probability that the test will produce a true positive when used on a population with the disease
  = TP / (TP + FN) —– true positives divided by everyone with the disease

Question 2

Specificity

Answer 2

• Positive results are really reliable, negative results are not as reliable
• Good Confirmatory test (to determine treatment) but can have false negatives
• sPecificity have reliable Positives
• Probability that the test will produce a true negative when used on a population without the disease
  = TN / (TN + FP) —- true negatives divided by everyone without the disease

Question 3

Positive Predictive Value

Answer 3

• Probability that someone who tests positive actually has the disease and isn’t a false positive
• Most useful when the prevalence is high (PPV increases as prevalence increases)
  = TP / (TP + FP)

Question 4

Negative Predictive Value

Answer 4

• Probability that someone who tests negative actually does not have the disease and isn’t a false negative
• Most useful when prevalence is low
  = TN / (TN + FN)

Question 5

P value definition

Answer 5

• Chance that the null hypothesis was rejected in error

- Odds that the null was correct and the results were due to chance

Question 6

Type I error

Answer 6

• Rejected the null hypothesis in error

- Probability of a type I error is the same as the p value

Question 7

Type II error

Answer 7

• Accepted the null hypothesis in error

Question 8

Validity

Answer 8

• Whether a test actually measures what it’s intended to measure
• Internal validity reflects accuracy
• External validity reflects generalizability

Question 9

Reliability

Answer 9

• Consistence or repeatability of scores

Question 10

Intention to treat

Answer 10

• All patients remain in the original groups to which they were initially randomly assigned in the study

Question 11

Number needed to treat

Answer 11

• Number needed to treat to prevent one adverse effect
• NNT = 1 / absolute risk reduction
• Absolute risk reduction = rate in untreated group - rate in treated group

Question 12

Incidence

Answer 12

Newly diagnosed cases in a given period of time

Question 13

Prevalence

Answer 13

Total number of cases of disease existing in a population at a given time

Question 14

Standard error

Answer 14

Describes how accurate the sample mean value used in the analysis is compared to the true population mean value

Question 15

Confidence interval

Answer 15

Measure of the reliability of your result

Question 16

Pre-test probability

Answer 16

Best estimate of the probability that a condition is present before you start diagnostic testing

Question 17

Likelihood ratio

Answer 17

Likelihood that a person who has the condition will have a positive test result

• LR > 1 increases the probability that the target condition is present
• LR < 1 makes condition less likely

Question 18

Absolute risk

Answer 18

Dividing number of patients who develop disease by total patients exposed
= A / (A+B)

Question 19

Relative risk

Answer 19

Probability of an outcome in the exposed group to the probability of the outcome in an unexposed group
= (A / (A+B)) / (C / (C+D))

Question 20

Odds ratio

Answer 20

Odds of an outcome in one group compared to the odds of that outcome in another group
= (A/B) / (C/D)

Question 21

Order of best study types

Answer 21

• Systematic reviews, meta analysis
• Randomized, controlled trials
• Cohort studies
• Case control studies
• Cross sectional studies
• Case studies/case reports
• Expert opnions/editorials

Question 22

Randomized control trial benefits

Answer 22

• Blind study, randomly assigned
• Baseline groups are equal, no confounding variables
• Limits expectation bias of patient and reduces bias of interpreting results

Question 23

Cohort studies

Answer 23

• Compare a group with an exposure to a control group without an exposure
• Limitations: need large sample size and long time to do they study

Question 24

Case control studies

Answer 24

• Compare patients with the disease and patients without disease and then check for risk factors
• Risk factor has to come before the outcome
• Useful only with a small sample size, a long latency period, or a rare outcome

Question 25

Cross sectional studies

Answer 25

• Observational, good for looking at associations between two measured factors at one point in time
• Limitations are risk of confounding variables and results can’t be used to infer causality

Question 26

Systematic reviews

Answer 26

Require: specific clinical question, thorough search for studies, clear explanation for which studies were considered and which were not, descriptive results section summarizing the findings

Question 27

Definition of brain death

Answer 27

Patients in a coma lack wakefulness and lack awareness of self environment. Patients in a vegetative state lack awareness but do have wakefulness.

Question 28

Sibling donor rules

Answer 28

Both donor and recipient are to benefit (mostly psychological to donor so if sibling has severe cognitive disabilities they are not going to benefit), risk to donor is minimal, absence of coercion

Question 29

Maternal-fetal conflicts

Answer 29

• Autonomy and bodily integrity of mother is critical and must be honored
• Can’t legally force a mom into a C-section for any reason

Question 30

Assent

Answer 30

• Willingness to accept treatment

- It is preferred for kids to agree to the treatment but since they’re minors, it’s not required like consent

Question 31

Newborn screening guidelines to include disease

Answer 31

• Disease should have a significant deleterious effect on the child, have effective treatment available if diagnosed early, have a screen that is acceptable to the population

Question 32

Newborn screening positives/negatives

Answer 32

High rate of false positives so need more definitive testing (but can also have some false negatives)

Question 33

Ethics for correcting ambiguous genitalia

Answer 33

• Decision should be multidisciplinary approach
• Possibility of gender change in adulthood should be factored in and surgery should be reversible if possible, fertility should be preserved if able

Question 34

Ethics for HIV positive patients

Answer 34

• Disclose slowly over time to child
• Participation in close contact sports where blood and bodily fluid transmission is likely is not recommended
• It is NOT mandatory for parents to disclose a child’s positive HIV status to the school

Question 35

Children exposed to domestice violence are at risk for

Answer 35

• Physical injury
• Aggression with their peers
• Separation anxiety as toddlers
• School failure as adolescent as well as risky sexual behavior

Question 36

Foster care health rules

Answer 36

• Health screen should be done within 72 hours of placement into foster care
• Comprehensive health assessment within 30 days

Question 37

Most common type of medical error

Answer 37

Medication error

Question 38

Disclosing medical errors to family

Answer 38

• Be totally transparent, why it happened, how it will impact them, steps being taken to prevent it from happening again
• Shown to reduce litigation and decrease settlement amounts