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3.4.2 Outcomes recommended by EMA research guidelines 23<br />

Whilst all <strong>the</strong> outcomes specified by NICE were reported (with <strong>the</strong> exception <strong>of</strong> HRQoL), some <strong>of</strong> <strong>the</strong><br />

outcomes specified in <strong>the</strong> EMA document were not reported. The EMA guidelines recommend<br />

composite primary outcomes:<br />

Non-inferiority trials: The combined incidence <strong>of</strong> recurrent DVT/PE <strong>and</strong> VTE-related deaths,<br />

with secondary analyses <strong>for</strong> each individual component separately.<br />

Superiority trials: The combined incidence <strong>of</strong> recurrent DVT/PE <strong>and</strong> all deaths, with<br />

secondary analyses <strong>for</strong> each individual component separately.<br />

The EMA primary outcomes were not reported in <strong>the</strong> corresponding EINSTEIN trials. However, all<br />

<strong>the</strong> individual <strong>of</strong> <strong>the</strong>se composite primary outcomes were reported. In addition, <strong>the</strong> composite primary<br />

outcomes specified by <strong>the</strong> EMA were not specified in <strong>the</strong> NICE scope, <strong>and</strong> <strong>the</strong> ERG does not feel that<br />

<strong>the</strong>ir omission is problematic; composite outcomes are generally not used in economic analyses as<br />

Superseded –<br />

<strong>the</strong>re are differential impacts on both costs <strong>and</strong> utility <strong>for</strong> <strong>the</strong> constituent events, <strong>and</strong> whilst composite<br />

outcomes may seem to have simplicity on <strong>the</strong>ir side, <strong>the</strong>y can be criticised <strong>for</strong> obscuring important<br />

differences in outcomes. 29<br />

3.4.3 Composite<br />

See<br />

primary endpoint<br />

Erratum<br />

This last point is <strong>of</strong> fur<strong>the</strong>r interest as <strong>the</strong> primary outcome defined by NICE is itself a composite<br />

outcome. VTE recurrence includes both DVT <strong>and</strong> PE. PEs are generally caused by parts <strong>of</strong> a DVT<br />

clot breaking <strong>of</strong>f <strong>and</strong> getting lodged in <strong>the</strong> arteries <strong>of</strong> <strong>the</strong> lungs. Whilst <strong>the</strong>se two events are<br />

manifestations <strong>of</strong> <strong>the</strong> same underlying condition, <strong>the</strong> clinical implications <strong>of</strong> each are different, with<br />

PE being more associated with death <strong>and</strong> CTEPH. There are also different costs associated with each.<br />

The use <strong>of</strong> a composite outcome might be argued to be valid if <strong>the</strong> constituent events are not thought<br />

to differ in <strong>the</strong>ir response to <strong>treatment</strong>, i.e. <strong>the</strong>y have similar reductions in relative risk. 29 If <strong>the</strong>re is<br />

reason to believe that <strong>the</strong> two events may behave differently, <strong>the</strong>n <strong>the</strong> composite outcome may not be<br />

appropriate.<br />

3.4.4 The diagnosis <strong>of</strong> primary outcomes<br />

The diagnosis <strong>of</strong> DVT <strong>and</strong> PE, <strong>for</strong> both index events <strong>and</strong> recurrence, described in <strong>the</strong> MS are largely<br />

consistent with those recommended by <strong>the</strong> European Medicines Agency (EMA) Committee <strong>for</strong><br />

Proprietary Medical Products (CPMP) 23 guidelines <strong>for</strong> <strong>the</strong> evaluation <strong>of</strong> new technologies <strong>for</strong><br />

managing VTE. Exceptions are discussed later in <strong>the</strong> report in section 4.2.1.3, “difference between<br />

expected <strong>and</strong> confirmed events”.<br />

30<br />

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

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