Rivaroxaban for the treatment of deep vein thrombosis and ...

In addition to the above, the manufacturer also conducted a series of multivariate, deterministic
sensitivity analyses, varying several parameters at the same time. Analyses conducted are presented in
Table 30.
Table 30: Multivariate SA conducted by the manufacturer (reproduction of Table 53, p.
158, MS, 1 November 2011)
Group parameters Individual parameters covered
Cost of ambulatory visits (OPs by
different treatment setting plus district
Cost of all types of monitoring visits for VKA and
rivaroxaban; cost of nurse visit
nurse)
Cost of inpatient treatments Cost of inpatient treatment for DVT and PE episodes; cost
of CTEPH surgery
Cost of outpatient treatment parameters Doppler ultrasound; CT angiography; Chest X ray; ECG;
D-dimer; Emergency admission
Cost of treating bleeds (Major and
minor)
Cost of CRNM bleeds and major EC and IC bleeds
Cost of treating PTS (mild/moderate Cost of PTS management (mild/moderate and severe) for
and severe, all years)
Yr1 and Yr2+
Cost of treating stroke (initial and
subsequent cycles)
Cost of major intra-cranial and post intra-cranial bleeds
Duration of utility impact for VTE and Duration of utility impact for DVT, PE, extra- and intra-
Bleed events
cranial bleeds
State-related mortality (all parameters) All mortality parameters for the probability of death with
event
State-related
parameters)
utility weightings (all All utility parameters
VKA OAC monitoring Parameters for VKA drug monitoring
5.2.1.12. Probabilistic Sensitivity analysis
The manufacturer conducted PSA over 1,000 iterations. The manufacturer varied the probabilities for
dual LMWH/VKA therapy of recurrent VTEs, major bleeds, CRNM bleeds and all other clinical
events, according to Beta distributions. The treatment effects in relation to efficacy and safety
variables for rivaroxaban vs. dual LMWH/VKA therapy were sampled from a lognormal distribution.
Utilities were sampled according to Beta distributions using the 95% CI or IQR where available. Unit
costs were sampled according to Gamma distributions with means equal to the point estimates and
standard errors assumed to be equal to 30% of those means.
The ERG has some serious concerns with the PSA conducted by the manufacturer, notably in cancer
patients;
1) The manufacturer sampled the unit costs assuming an arbitrary 30% standard error around the
mean. It is unclear why the unit costs from the NHS reference costs were not sampled with
the standard error calculated from the IQR for example.
117
Copyright 2012 Queen's Printer and Controller of HMSO. All rights reserved.