Pediatric Clinics of North America - CIPERJ

296 O’BRIEN
such as, ‘‘Observation for ITP patients is the most costeffective
strategy, unless the incidence of intracranial hemorrhage is greater
than 5%.’’
Published examples of decision analyses in pediatric hematology
Over the past decade, several decision analyses have been performed that
address clinical dilemmas in pediatric hematology. A comprehensive list is in
Table 1, but three examples warrant further discussion.
Management options for inhibitors in hemophilia include eradicating the
inhibitor via immune tolerance induction or treating bleeding episodes with
large quantities of hemostatic agents. In a study by Colowick and colleagues
[29], the investigators constructed a decision analysis model to compare the
expected clinical outcomes and costs over a lifetime for a typical 5 year old
who has severe factor VIII deficiency and high inhibitor levels. Only the
costs of factor concentrates were considered rather than the full complement
of direct and indirect health care costs, as recommended by the Panel on
Cost-Effectiveness. The investigators stated, however, that they considered
only factor costs because many studies have demonstrated that factor concentrates
account for 80% to 90% of total costs in managing patients who
have hemophilia in inpatient and outpatient settings. Because the timeline of
interest is a lifetime, the investigators appropriately used a Markov model.
The patient could experience one of seven possible health states: three shortterm
(acute bleed) states, three chronic joint disease states, and death. In this
model, the immune tolerance strategy was cost saving and clinically superior,
costing $1.7 million less and providing 4.6 additional life-years for
each patient. Because decision analysis has the advantage of being able to
consider any timeframe, this study was able to show that an intervention
that is extremely expensive upfront actually is cost saving when considered
over a child’s lifetime.
To date, no clinical trial has examined whether or not patients who have
sickle cell disease and a high risk for stroke would have better outcomes with
a chronic transfusion program or bone marrow transplantation (BMT). In
a study by Nietert and coworkers [30], decision analysis was used to compare
the number of QALYs experienced by patients who had abnormal cerebral
flow velocities treated with periodic blood transfusions (PBT) or
BMT. One weakness of this study is that although QALYs were the major
outcome of interest, utility estimates were based solely on the opinion of two
of the investigators because of the absence of direct reports of quality of life
from sickle cell patients. Although the investigators noted that their estimates
were within the ranges of the Health and Activities Limitation Index
measurements for other chronic diseases, this study would have been
strengthened by obtaining some utility measurements from patients who
had sickle cell anemia and their families. In a recent study of therapy