Download the full report (130 p.)

KCE Reports 74 Hyperbaric Oxygenation Therapy 45
Table 8. Base case model parameters 81
healing minor LEAs major LEAs
HBOT treatment 55% a 35% a 10% a
No HBOT treatment 33% a 26% a 41% a
Mortality b 2.8% c 2.8% 16.3% d
LEA: lower extremity amputations
a: based on the average of four prospective, controlled clinical studies: Faglia et al., 98 Doctor et
al., 99 Baroni et al., 100 and Zamboni et al. 101; b: the mortality rate was assumed to be constant over
the 12-year period; c: Bild et al. 102; d: Baddeley et al. 103
The time window of the analysis was 1, 5 and 12 years. The 5-year interval was chosen
to represent the private payers’ perspective, because 5 years later the patients
automatically become Medicare beneficiaries.
The 12-year interval was selected to represent the societal perspective, because the life
expectancy for people at age 60 was approximately 20 years, 104 and the life expectancy
for people with diabetes would be approximately 8 years shorter than that of people
without diabetes. 105 A discount rate of 3% was applied to adjust QALYs gained in future
years.
Cost items included were costs for HBOT ($407 per treatment, inclusive technical and
physician fees), and costs for a minor or major LEA ($40 673 and $39 404 respectively,
inclusive surgery, inpatient care, rehabilitation, first-year outpatient visits, and physician
fees). An average of 29 HBOT sessions per case was taken into account. Costs were
inflated to 2001 dollars. Finally, scenario analysis was conducted to measure the range
of CE ratios between the least and most efficacious input parameters of the four
prospective, controlled studies.
Due to HBOT, 155 cases of major LEAs were averted (205 versus 50 LEAs in the
control and HBOT group, respectively) and approximately 50.2, 265.3, and 608.7
QALYs were gained at years 1, 5, and 12, respectively, in the hypothetical cohort.
There was also an increase of 45 cases of minor LEAs (130 versus 175 LEAs in the
control and HBOT group, respectively). The incremental cost-effectiveness ratio (ICER)
was estimated to be $27 310, $5 166, and $2 255 per QALY, at years 1, 5, and 12,
respectively. In the scenario analyses, the ICERs varied substantially. Results were very
sensitive to the efficaciousness probabilities. For example, the CE ratio at year 1 was
$142 923, $27 310 per QALY, and cost saving ($-72 799) in the worst, base, and best
case scenarios, respectively. Results were also sensitive to the quality weights, especially
for major LEA, the number of HBOT sessions per case, the HBOT cost per treatment,
and the treatment costs of major and minor LEA per case.
The authors concluded that HBOT in the treatment of diabetic ulcers was cost
effective, especially in the long term. They also acknowledged that results were limited
by the clinical studies that provide the basis of the estimates.
4.3.1.3 Hailey et al. 79
The Canadian study of Hailey et al. (2007) used a decision model to estimate the costeffectiveness
of adjunctive HBOT in comparison with standard care alone. The model
used a 65-year-old patient cohort with diabetic foot ulcers. The model was very similar
to that of Guo et al. 81 with the addition of one extra health state, i.e. unhealed. Results
were expressed in costs per QALY. The related utilities for the health states were 0.6
for a primarily healed wound, 0.61 for healed with a minor LEA, 0.31 for healed with a
major LEA, 0.44 if unhealed with no related surgery, and 0 for death. 97, 106 Table 9
presents outcome probabilities in the first year and mortality parameters.