Lecture 5 Flashcards
Outcome definition
results, conditions or events associated with individual study patients that are used to assess study treatement
primary outcomes
assess the main effect of an intervention and drive conclusions about the effectiveness of the intervention under study
secondary outcomes
evaluate additional effects of intervention (side effects, cost)
effect size
difference between the value of the “success” varible (primary outcome) in the control group and that in the test group
-expressed as absolute difference or relative difference
-estimate effect size from previous studies
-large effect size needs smaller sample size
-small effect size needs larger sample size
clinical outcome
directly measures patient health or well being (morbidity/mortality)
-true picture
-can be difficult to measure, long term effect
-example: patient is cancer free for 5 years
surrogate outcome
laboratory measurement or physical sign used as a substitute for clinically meaningful outcome
-need smaller sample size, shorter duration, lower cost
-may not be valid prediction of clinial outcome
-example: tumor regression in patient
selective reporting of outcomes (3)
-subset of study outcomes (not all outcomes reported)
-selective reporting of specific outcome (one outcome at one time point is reported, not all)
-incomplete reporting of specific outcome (difference in means reported without CI or standard error)
selection of outcomes (six questions to ask)
-why this outcome (matches obkective of study)
-what health condition and population (ie severity)
-How outcome will be measured (valid, reliable, feasible)
-who appropriate source of information (physician, patient, proxy, reseacher)
-where location of outcome measurement (at home, in doctor office, hospital)
-When responsiveness of measure (take into consideration ability of instrument to detect change over time for the measured construct)
four key properties of outcome
-validity
-reliability
-feasibility
-responsiveness
Adaptive design
allows for prospectively planned modifications to one or more aspects of the design based on acumulating data from subjects
-can lead to unplanned changes based on results or protocol amendments based on external sources
-can adapt: patient pop, sample size, treatement arm selection, patient allocation, endpoint, statistical aspects
benefits of study adaptation (3)
-statistical efficieny (greater chance of detecing drug effect at expected sample size)
-ethical (stop trial if drug not effective, or enough evidence of beneficial effect)
-understanding drug effects (improves estimation of dose-response relationship with adaptive dose selection)
limitations of study adaptation (3)
-methodology challenges in controlling bias, reliability and estimation of treatment effects
-operational challenges to maintain study integrity
-interpretability challenges due to changes in estimand of interest
toxicology definition
study of adverse effects of foreign compunds on living organisms
adverse effect definition
undesrieed harmful effect resulting from medication use
toxicity
capacity of chemical to cause injury
