Pediatric Clinics of North America - CIPERJ

292 O’BRIEN
diagnosis-related groups, laboratory costs can be obtained from the Clinical
Diagnostic Laboratory Fee Schedule, and the costs of physician visits, tests,
and procedures can be estimated using Healthcare Common Procedure
Coding System codes. More information about these data sources and
the Physician Fee Schedule Search can be found at the Centers for Medicare
and Medicaid Services Web site [13]. In 1996, the Panel on Cost-Effectiveness
in Health and Medicine published consensus-based recommendations
for the conduct of cost-effectiveness analyses [14]. This document is an excellent
resource that addresses the proper methodology for measuring costs
and health consequences, incorporating time preferences and discounting,
and handling uncertainty in cost-effectiveness analyses.
Economic evaluations that take a societal point of view, as recommended
by the Panel on Cost-Effectiveness in Health and Medicine, must include the
indirect costs of health care. These costs include patient transportation expenses
for office and laboratory visits and costs for patient time. Productivity
losses, or costs for time, are yet to be well described for children and
adolescents. A common technique for estimating the costs of adult patient
and parent time is to base these costs on the average hourly wage of a United
States non–farm production worker, published annually by the United
States Department of Labor, Bureau of Labor Statistics [15].
Although usually considered under the umbrella term of ‘‘cost-effectiveness
analyses,’’ it is important to distinguish cost-effectiveness from costutility
analyses. Both studies measure costs in the same manner; it is the
benefits that are measured in different metrics [16]. In a cost-effectiveness
analysis, costs all are related to a single, common effect. For example,
an investigator could compare ultrasonography to venography in terms
of number of upper extremity DVTs detected or primary versus secondary
hemophilia prophylaxis in terms of number of joint bleeds. In a cost-utility
analysis, outcomes are measured in terms of the value placed on the outcome
rather than the outcome itself, which usually is expressed as qualityadjusted
life-years (QALYs). Total QALYs are calculated for each strategy
by multiplying the time spent in a state of health by the utility value of
that particular health state. Utilities represent a patient’s preference for
a particular health state and can range from 0 (death) to 1 (perfect health).
There are two main advantages to the use of QALYs as an outcome measure:
(1) the measure combines length of life and quality of life into a single
outcome and (2) the measure allows direct comparison of health benefits
across different diseases, patient populations, and studies [17].
Utilities can be measured in several different ways. An investigator can
measure utilities directly for the decision analysis model by performing
a choice-based valuation technique, such as the standard gamble or time
trade-off method, in a representative sample of the general population. In
the standard gamble, the respondent is asked to consider one health state
with a certain outcome and one that involves a gamble between two additional
health states. The probability of the gamble is varied until the