{"id":456,"date":"2016-11-03T08:50:42","date_gmt":"2016-11-03T08:50:42","guid":{"rendered":"https:\/\/www.transplantevidence.com\/news\/?p=456"},"modified":"2016-11-03T08:50:42","modified_gmt":"2016-11-03T08:50:42","slug":"quality-and-consistency-of-outcome-reporting-in-transplant-clinical-trials","status":"publish","type":"post","link":"https:\/\/www.transplantevidence.com\/news\/2016\/11\/03\/quality-and-consistency-of-outcome-reporting-in-transplant-clinical-trials\/","title":{"rendered":"Quality and consistency of outcome reporting in transplant clinical trials"},"content":{"rendered":"

Much focus is placed upon the methodological quality of clinical trials, and the impact that it has on the risk of bias at a study level. \u00a0An often neglected area is the reporting quality of the manuscripts from trials, which can also have a big impact on the interpretation of results. A recent paper in Clinical Transplantation<\/a>, published by Samia Hussain (a past research fellow\u00a0at the CET), highlights this problem in 182 clinical trials of immunosuppression following renal transplantation published between 2010 and 2014.<\/p>\n

Selective outcome reporting can result in “reporting bias” – a skewed perception of the benefits\/risk of an intervention resulting from the reporting of only a subset of outcomes of interest. \u00a0This may result from deliberate manipulation – a decision by the authors not to report an outcome due to unfavourable characteristics. \u00a0More often, however, it arises from a perceived irrelevance of an outcome – if a study is not powered to a particular secondary outcome, and the results do not reach statistical significance, it is less likely to be reported. \u00a0This is potentiated by journal editorial policy – word limits for articles mean that seemingly uninteresting outcomes will often be removed from study reports.<\/p>\n

On the face of it, this doesn’t seem like too much of a problem. \u00a0If the effect of an intervention on an outcome is not significant, then reporting it may not seem important. \u00a0However, the inability to detect<\/em> an effect due to lack of power (particularly for secondary outcomes and rare events) is not the same as there truly being no effect<\/em>. The problem can be demonstrated by considering what would happen if the results of the study were subjected to a meta-analysis. If only those studies that found a significant effect on a given outcome report that outcome, then the results of the meta-analysis will be biased towards a much larger effect size. \u00a0If all of the studies report the outcome, both significant and non-significant, then the effect size seen in meta-analysis will be much smaller. By suppressing results for relevant outcomes, we are introducing bias.<\/p>\n

Often, outcomes are reported, but\u00a0data are missing. \u00a0Insufficient data can also preclude the use of the studies in meta-analysis; for example, missing measures of variance for continuous outcomes are a common problem. \u00a0Samia’s analysis\u00a0suggests that nearly 10% of outcomes reported in clinical trials of immunosuppression have missing data that would make inclusion in meta-analysis impossible.<\/p>\n

Another issue with \u00a0is the inconsistency in outcome definitions. \u00a0The same outcome may be defined or measured differently in different studies, leading to variability in the incidence. \u00a0Very often, the tool, test or scale used to measure an outcome is not defined at all. \u00a0In Samia’s analysis, 45% outcomes identified did not have a clear definition. \u00a0Whilst definition and reporting of efficacy outcomes was reasonably good (90% were clearly defined), safety outcomes (29%) and patient-reported outcomes (13%) were far less likely to have clear definitions.<\/p>\n

So how do we address these issues? The concept of a “core outcome set” has been discussed here before<\/a>. If we define a minimum outcome set\u00a0that should be reported in all trials in a particular area, as well as the tools that should be used to measure these outcomes, then we can improve consistency and completeness. \u00a0If these outcomes are universally reported, then we can apply the same core outcome set to systematic reviews in the field, reducing the risk of reporting bias. \u00a0The SONG initiative (SONG-Tx)<\/a> is an international collaboration attempting to create a core outcome set for trials in renal transplantation, and will be an important step forward in the transparent reporting of transplant trials.<\/p>\n","protected":false},"excerpt":{"rendered":"

Much focus is placed upon the methodological quality of clinical trials, and the impact that it has on the risk of bias at a study level. \u00a0An often neglected area is the reporting quality of the manuscripts from trials, which can also have a big impact on the interpretation of results. A recent paper in […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[163],"tags":[192,195,201,239,250],"class_list":["post-456","post","type-post","status-publish","format-standard","hentry","category-trials","tag-cet","tag-clinical-research","tag-core-outcomes","tag-kidney-transplantation","tag-methodology"],"_links":{"self":[{"href":"https:\/\/www.transplantevidence.com\/news\/wp-json\/wp\/v2\/posts\/456","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.transplantevidence.com\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.transplantevidence.com\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.transplantevidence.com\/news\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.transplantevidence.com\/news\/wp-json\/wp\/v2\/comments?post=456"}],"version-history":[{"count":1,"href":"https:\/\/www.transplantevidence.com\/news\/wp-json\/wp\/v2\/posts\/456\/revisions"}],"predecessor-version":[{"id":457,"href":"https:\/\/www.transplantevidence.com\/news\/wp-json\/wp\/v2\/posts\/456\/revisions\/457"}],"wp:attachment":[{"href":"https:\/\/www.transplantevidence.com\/news\/wp-json\/wp\/v2\/media?parent=456"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.transplantevidence.com\/news\/wp-json\/wp\/v2\/categories?post=456"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.transplantevidence.com\/news\/wp-json\/wp\/v2\/tags?post=456"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}