Flashcards in Pharm: Benefit vs. Risk of Drug Therapy Deck (16):
According to studies discussed, do physicians and other healthcare professionals use evidence-based medicine effectively?
Unfortunately, no. Physicians fall victim to the same reporting tricks that make patients view outcome measures differently.
What is EER?
experimental event rate; the rate at which the experimental agent or variable has an outcome effect
What is CER?
control (or comparison) event rate; the rate at which the outcome occurs in the control group
What is relative risk?
the probability of the outcome in treated patients relative to the probability of the outcome in untreated patients
How is relative risk calculated?
RR = EER / CER
What is the relative risk ratio?
the difference in proportions of untreated and treated patients who experience a particular outcome relative to the proportion of untreated patients who would experience the outcome
How is the relative risk ratio calculated?
RRR = (CER -- EER) / CER
True or false: the relative risk ratio tends to hide small differences in effect.
False - it tends to exaggerate small differences. For example: say a drug reduces the rate of death in a sick patient population. Placebo group sees 10% death while drug group sees 8% death. The RR is 2% different but the RRR is 20% less in the drug group; makes a small difference (2%) look bigger/exaggerated (20%).
What is absolute risk?
the absolute difference in the proportion of treated and untreated patients who experience an outcome
Absolute risk can have 2 forms, depending on whether risk goes up or down. What are they called?
Absolute risk reduction
Absolute risk increase
Which method of reporting risk is the most straightforward?
How is the absolute risk calculated?
ARR = CER – EER
What is the NNT?
Number Needed to Treat; this number is the number of people needed to undergo treatment before one person will experience benefit; another way of reporting an outcome, ex: if the absolute risk reduction is 2%, the NNT is 50 because 2 are benefitted per every 100 treated
How is NNT calculated?
NNT = 100 / ARR
What is the number needed to harm?
the complement to NNT when examining the number of patients who will be treated before a patient experiences harm from the treatment; this can be lower than the NNT and is important to consider when evaluating risk/benefit