CUA Flashcards
CUA is a type of ___
CEA
what does CUA stand for
cost utility analysis
what is CUA
a type of CEA in which benefits are expressed as the number of life years saved adjusted to account for loss of quality from morbidity of the health outcome or side effects from the intervention
in a CUA, ____ are assigned to outcomes
values (utilities)
where do you obtain utilities
literature
convenience sample
measure from society
measure directly from patients (direct approach is decision theory, indirect approach is psychometric method)
how do we measure preferences?
direct: rating scale, standard gamble, time trade off
indirect: multi-attribute health status preference scores
what is the gold standard for measuring preferences
standard gamble
because it is framed under the condition of uncertainty
what is standard gamble
patients are asked to compare one option, whose outcome is to remain in the current state until death, with a second option that has an uncertain outcome.
probabilities are varied until the subject is indifferent to either treatment
what is time-trade off
used to determine how many years of life in excellent health are equivalent to life with a less desirable health state
time is varied until the individual is indifferent about the alternatives
what is multi-attribute health status preference score
measures how the general public values a given health state. combines different dimensions of health to compute a series of health preference values
(psychometric methods)
utility is a measure of ____
preference for a particular health state
what is QALY
quality adjusted life year
health utility measure which combines quality of life with life years gained
how do you calculate QALY
calculate AUC
when should quality be measured?
primary purpose of drug is palliative vs curative
drug somewhat effective but also fairly toxic
lifelong therapy administered to prevent complications of a relatively asymptomatic disease
why should we measure quality
length of life is not that important if the quality is bad
when do we know to use a CUA
when QOL is important outcome
intervention affects both morbidity & mortality
interventions compared have a wide range of different outcomes
ICER in a CUA
uses qaly
ICER= (cost A- cost B)/ (QALY A-QALY B)
strengths of CUA
integrates both quality & quantity of life into a common unit of measure: allows comparison of interventions on different dementions
limitations of CUA
questions based solely on calculation of QALY
measured in years so not useful for acute conditions
assumptions about QALYs
life and death are reference states (healthy 1, dead 0)
QALY only captures health-related utility
utility value of healthy life is set equal for each individual at birth
attributes of quality and quantity must be mutually independent
one full healthy year of life is ___ QALY
1.0
years of life in less than optimal health are scored ___ QALY
<1.0
QALY limitations
-are many small improvements (0.1 QALY) really equal to one large improvement (1.0 QALY)?
-improvement from 0.1-0.5 is valued the same as 0.5-0.9 but is it really?
two types of sensitivity analysis in CUA
one-way sensitivity analysis (OWSA)
probabilistic sensitivity analysis (PSA)
OWSA
change one parameter of a time keeping all others constant: will tell you the most influential parameters to your model
PSA
change all (or many) variables simultaneously
