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Outcome measure
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<h2 id="relevance">Relevance</h2> <p>Outcome measures used in trials should consider relevance to the target of the study. In clinical trials such measures of direct importance for an individual may be <a href="/facts/Survival_analysis/q8w13cjl">survival</a>, <a href="/facts/Quality_of_life/37ljmgAH">quality of life</a>, <a href="/facts/Disease/55eeQlGL">morbidity</a>, <a href="/facts/Suffering/gDdgz4lj">suffering</a>, <a href="/facts/Functional_impairment/vr9BPUxo">functional impairment</a> or changes in <a href="/facts/Symptom/BzP6MrTN">symptoms</a>.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> </p><p>Outcome measures can be divided into <a href="/facts/Clinical_endpoint/1I7oM6j3">clinical endpoints</a> which are directly relevant to the target and <a href="/facts/Surrogate_endpoint/qSWmMdt9">surrogate endpoints</a> (also called "proxy measures"), which are indirectly related.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> <a href="/facts/Cardiovascular_disease/HD420nMv">Death from cardiovascular disease</a> is an example of a clinical endpoint, whereas measurements of <a href="/facts/Blood_pressure/VtqqSM2J">blood pressure</a>, which is not normally associated with any symptoms, is a surrogate endpoint. Other examples of surrogate endpoints are <a href="/facts/Blood_lipoproteins/FUFotgeL">blood lipoproteins</a> and <a href="/facts/Bone_density/poUvLR69">bone density</a>.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> </p><p>Composite measures or combined measures are common in clinical research.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a><a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a> The rationale is that combining different outcome measures gives greater statistical power. For example, the composite measure "<a href="/facts/Killed_or_Seriously_Injured/AVTdyXBs">Killed or Seriously Injured</a>" is often used in studies of <a href="/facts/Road_safety/rbruv0AE">road safety</a>. While deaths are easier to count and are an outcome of undisputed importance, they are also much fewer than the number seriously injured; many of the "seriously injured" will not have experienced a major life event. However, composite measures should be used with care, particularly when surrogate endpoints are included.<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> A statistically significant effect of a composite measure can often be explained solely by effects of a surrogate endpoint or a variable that is less relevant. It is also possible that composite measures may mask negative treatment effects of truly important outcomes, such as death or cardiovascular events.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a> </p> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Ross, David A.; Morrow, Richard H.; Smith, Peter G. (2015). Outcome measures and case definition. Oxford University Press. doi:10.1093/med/9780198732860.003.0012. ISBN 9780191797675. <a href="9780191797675" target="_blank">9780191797675</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Assessment of methods in health care - A handbook (PDF) (Preliminarily ed.). Swedish Agency for Health Technology Assessment and Assessment of Social Services. April 2018. pp. 18–19. Retrieved 2019-08-28. <a href="https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf" target="_blank">https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Tripepi, G.; Jager, K.J.; Dekker, F.W.; Wanner, C.; Zoccali, C. (October 2007). "Measures of effect: Relative risks, odds ratios, risk difference, and 'number needed to treat'". Kidney International. 72 (7): 789–791. doi:10.1038/sj.ki.5002432. PMID 17653136. <a href="https://doi.org/10.1038%2Fsj.ki.5002432" target="_blank">https://doi.org/10.1038%2Fsj.ki.5002432</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Ross, David A.; Morrow, Richard H.; Smith, Peter G. (2015). Outcome measures and case definition. Oxford University Press. doi:10.1093/med/9780198732860.003.0012. ISBN 9780191797675. <a href="9780191797675" target="_blank">9780191797675</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Assessment of methods in health care - A handbook (PDF) (Preliminarily ed.). Swedish Agency for Health Technology Assessment and Assessment of Social Services. April 2018. pp. 18–19. Retrieved 2019-08-28. <a href="https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf" target="_blank">https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Ross, David A.; Morrow, Richard H.; Smith, Peter G. (2015). Outcome measures and case definition. Oxford University Press. doi:10.1093/med/9780198732860.003.0012. ISBN 9780191797675. <a href="9780191797675" target="_blank">9780191797675</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Ross, David A.; Morrow, Richard H.; Smith, Peter G. (2015). Outcome measures and case definition. Oxford University Press. doi:10.1093/med/9780198732860.003.0012. ISBN 9780191797675. <a href="9780191797675" target="_blank">9780191797675</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Ross, David A.; Morrow, Richard H.; Smith, Peter G. (2015). Outcome measures and case definition. Oxford University Press. doi:10.1093/med/9780198732860.003.0012. ISBN 9780191797675. <a href="9780191797675" target="_blank">9780191797675</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Assessment of methods in health care - A handbook (PDF) (Preliminarily ed.). Swedish Agency for Health Technology Assessment and Assessment of Social Services. April 2018. pp. 18–19. Retrieved 2019-08-28. <a href="https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf" target="_blank">https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Ross, David A.; Morrow, Richard H.; Smith, Peter G. (2015). Outcome measures and case definition. Oxford University Press. doi:10.1093/med/9780198732860.003.0012. ISBN 9780191797675. <a href="9780191797675" target="_blank">9780191797675</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Assessment of methods in health care - A handbook (PDF) (Preliminarily ed.). Swedish Agency for Health Technology Assessment and Assessment of Social Services. April 2018. pp. 18–19. Retrieved 2019-08-28. <a href="https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf" target="_blank">https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Ross, David A.; Morrow, Richard H.; Smith, Peter G. (2015). Outcome measures and case definition. Oxford University Press. doi:10.1093/med/9780198732860.003.0012. ISBN 9780191797675. <a href="9780191797675" target="_blank">9780191797675</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>Assessment of methods in health care - A handbook (PDF) (Preliminarily ed.). Swedish Agency for Health Technology Assessment and Assessment of Social Services. April 2018. pp. 18–19. Retrieved 2019-08-28. <a href="https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf" target="_blank">https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>Assessment of methods in health care - A handbook (PDF) (Preliminarily ed.). Swedish Agency for Health Technology Assessment and Assessment of Social Services. April 2018. pp. 18–19. Retrieved 2019-08-28. <a href="https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf" target="_blank">https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>Assessment of methods in health care - A handbook (PDF) (Preliminarily ed.). Swedish Agency for Health Technology Assessment and Assessment of Social Services. April 2018. pp. 18–19. Retrieved 2019-08-28. <a href="https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf" target="_blank">https://www.sbu.se/contentassets/76adf07e270c48efaf67e3b560b7c59c/eng_metodboken.pdf</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> </ol>