Apixaban for the prevention of venous thromboembolism in people ...

5.2.7 Health related quality of life
A systematic literature review was conducted to identify utility inputs for use in the model.
Each year 0.00029 was subtracted from a patient’s health state utility value before the QALYs
for that year are calculated. 53 This age decrement was based on the EQ-5D US tariff. Below
the utility values and decrements used in the model are listed per health state.
Well or treated VTE
To represent the quality of life of a fully recovered well patient following surgery, the model
uses a value of 0.78 per year for the health state of well derived from EQ-5D UK population
norms by Kind et al. 54 The model uses a utility decrement of -0.01 for one month to represent
the drop in quality of life of a patient experiencing a VTE event but receiving treatment for it
(the treated VTE state in the model). This utility estimate came from Gage et al. 55 and was
based on a sample of 70 patients with atrial fibrillation using the time trade-off method.
PE and DVT
The model uses utility decrements for PE and DVT (symptomatic proximal and distal) of -
0.08 from Ingelgard et al. 56 This utility value is based on data obtained from 121 Swedish
outpatients with DVT using EQ-5D (tariff used unknown).
Post Thrombotic Syndrome (PTS)
The model uses utility decrement of -0.02 for mild to moderate PTS and -0.07 for severe PTS
from Lenert and Soetikno. 57 These values were obtained from a sample of 30 healthy women
using the standard gamble method.
Major bleed and disability following intracranial haemorrhage
A utility decrement of -0.03 is used for major bleed and was the median taken from a study by
Robinson et al. 58 of 54 patients with atrial fibrillation in which the standard gamble method
was used. A utility decrement of -0.49 is used to represent the drop in quality of life for
patients who become disabled following an intracranial bleed. This decrement is based on an
42, 43
average of 109 published stroke utility decrements reported in the studies by Wolowacz
and BoehringerIngleheim. 47
Table 5.9 Utility input (Table 69&71-74 MS)
State Utility
value or
decrement
Confidence
interval or
Std Error
47
Reference Duration Reference
THR TKR
General male population 0.78 0.018543 Kind54 N/A N/A
General female population 0.78 0.015504 Kind54 N/A N/A
Death 0 N/A Assumption
Hospitalization Period Days Days
PE –0.08 0.004082* Ingelgard 56 5.63 7.49 Assumption
Symptomatic Distal DVT –0.08 0.949 1.73
Symptomatic Proximal DVT –0.08 0.949 1.73
Asymptomatic DVT 0.0 N/A N/A N/A
Intracranial haemorrhage –0.49 0.03* Boehringer 47 90 90
Major Bleed – other –0.03 0.001531* Robinson 58 5.63 7.49
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