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

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The searches identified 2,811 potentially relevant studies <strong>and</strong> six studies were considered relevant by<br />

<strong>the</strong> manufacturer after review <strong>of</strong> <strong>the</strong> titles, abstracts <strong>and</strong> full papers. Two fur<strong>the</strong>r studies were included<br />

by <strong>the</strong> manufacturer <strong>for</strong> <strong>the</strong> population baseline 66 <strong>and</strong> <strong>the</strong> post IC bleed health state. 67<br />

The manufacturer’s economic model assumed a baseline utility value <strong>of</strong> 0.825 based on <strong>the</strong> l<strong>and</strong>mark<br />

national EQ-5D survey conducted by Kind et al (1998) measured using <strong>the</strong> visual analogue scale<br />

(VAS). 66 The study included members <strong>of</strong> <strong>the</strong> public aged 18 <strong>and</strong> over.<br />

The utility value <strong>for</strong> <strong>the</strong> DVT, PE, EC bleed, IC bleed, CRNM bleed <strong>and</strong> PTS, was calculated<br />

applying a disutility (or decrement in utility) to <strong>the</strong> baseline utility value (0.825). The relative<br />

decrement in utility was taken from an evaluation <strong>of</strong> patient preferences in VTE conducted by<br />

Locadia et al. 68 The manufacturer acknowledged <strong>the</strong> limitations within <strong>the</strong> study in that preferences<br />

were elicited by patients ra<strong>the</strong>r than <strong>the</strong> general public. However, <strong>the</strong> manufacturer stated that this<br />

study provided time trade <strong>of</strong>f utilities <strong>for</strong> <strong>the</strong> different health states. The manufacturer also assumed<br />

that <strong>the</strong> relative decrement in utility <strong>for</strong> major EC bleed was similar to GI bleed <strong>and</strong> that <strong>the</strong> relative<br />

decrement in utility <strong>for</strong> major IC bleed was similar to haemorrhagic stroke. The relative decrement in<br />

utility <strong>for</strong> severe PTS was taken from Lenert et al. 69<br />

In addition to <strong>the</strong> above, <strong>the</strong> manufacturer assumed a utility value <strong>of</strong> 0.56 <strong>for</strong> patients with CTEPH<br />

based on Meads et al. 70 using <strong>the</strong> Cambridge PH Outcome Review (CAMPHOR) instrument<br />

calculated in a sample <strong>of</strong> 308 patients. The manufacturer used this data stating that <strong>the</strong> estimates from<br />

this instrument were comparable to estimates using <strong>the</strong> EQ-5D.<br />

The manufacturer did not find a utility value following an IC bleed. There<strong>for</strong>e (<strong>for</strong> <strong>the</strong> post IC bleed<br />

health state), <strong>the</strong> manufacturer assumed that <strong>the</strong> utility would be similar to patients with a stroke <strong>and</strong><br />

assumed a utility <strong>of</strong> 0.713 taken from Rivero-Arias et al.(2008) 67 because <strong>of</strong> <strong>the</strong> similarities in<br />

functional outcomes after a stroke or IC bleed. 71 The utility value was estimated using <strong>the</strong> EQ-5D in a<br />

sample <strong>of</strong> 1,283 people who had experienced stroke or transient ischemic attacks measured over two<br />

years. 67<br />

In addition, <strong>the</strong> manufacturer also identified a study reporting a decrease in utility <strong>for</strong> patients<br />

attending an anticoagulation clinic treated with warfarin or LMWH. 72 However, no reduction in QoL<br />

was assumed in <strong>the</strong> basecase economic model.<br />

110<br />

Copyright 2012 Queen's Printer <strong>and</strong> Controller <strong>of</strong> HMSO. All rights reserved.

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