1.

Define sensitivity.

The percent of test results that are truly positive. True positives divided by the total number of positive results.

2.

Define specificity.

The percent of test results that are truly negative. True negatives divided by the total number of negative results.

3.

Define number needed to treat.

Number needed to treat (NNT) is the number of patients that need to be treated to prevent an outcome. It is 100 divided by the absolute difference between the percent in the intervention group minus the percent in the control group NNT = 100/ARR = [incidence in control group – incidence in treatment group]. E.g. If the absolute risk reduction (ARR) is 40% in control group and 20% in treated group, NNT = 100/(40 – 20) = 100/(20) = 5; you need to treat five people for the time period used in the study to get one occurrence of the outcome.

4.

Define absolute risk reduction (ARR).

The absolute risk reduction is the absolute difference of the percent of an outcome in the control group minus the percent outcome in the intervention group.

ARR = incidence (control group) – incidence (intervention group)

5.

Define relative risk reduction (RRR).

The relative decrease of an outcome compared to the risk of that outcome in the control group. It is calculated by dividing the absolute risk reduction by the risk in the control group. RRR = (incidence [control group] – incidence [treated group])/incidence (control group)

6.

Define p value.

The degree or limits of statistical significance. In medicine, a p value of <0.05 implies statistical significance (that the findings have a less than 5% chance of being incorrect).

7.

Define confidence interval.

It is a measure of variance, predicting statistical significance. It is clinically similar to a p value, and notes the range of a measure where the actual number statistically lies.

8.

What is the FDA’s process to evaluate the safety and efficacy of new medications?

Phase 1: (Safety) a new medication is given to healthy adults to determine the drug’s most common side effects and the drug’s metabolism and excretion.

Phase 2: (Efficacy) small study to determine if the drug shows benefit in patients who have a certain disease or condition.

Phase 3: (Safety and efficacy) much larger scale trials in patients with a given disease but in conjunction with other medications to determine safety and efficacy.

Phase 4: (Post marketing) after approval, the medication is further studied to determine more about long-term risks, optimal use, and efficacy in different populations.

9.

What is primary prevention?

Primary prevention involves information or interventions directed toward the entire population. It includes health promotion (exercise, eat properly, etc.) and protection against exposures (wear seat belts, drink clean water) that can lead to health problems.

10.

What is secondary prevention?

Measures taken based on potential risk factors like age or other objective measures (BMI, blood pressure, etc.). They are used early in the course of an illness to identify those who are affected but are without symptoms (screening for hypertension or colorectal cancer).

11.

What is tertiary prevention?

Steps taken after the development of a condition that help rehabilitate patients by reducing complications, improving their quality of life, and extending their years of productivity (pneumococcal immunization after splenectomy, using statins post myocardial infarction [MI], etc.).

12.

What is a systematic review?

A systematic review is a type of medical study that uses unbiased methods to find, evaluate, and combine outcomes of similar studies to determine if the combined data finds a different outcome than any one study.

Studies included in a systematic review are screened to include those of high quality and low risk of bias.