{"id":1265,"date":"2016-03-11T20:33:39","date_gmt":"2016-03-11T19:33:39","guid":{"rendered":"http:\/\/stg-blogs.bmj.com\/adc\/?p=1265"},"modified":"2016-03-02T15:04:30","modified_gmt":"2016-03-02T14:04:30","slug":"basics-blame-it-on-me","status":"publish","type":"post","link":"https:\/\/stg-blogs.bmj.com\/adc\/2016\/03\/11\/basics-blame-it-on-me\/","title":{"rendered":"Basics: Blame it on me"},"content":{"rendered":"<p>In my clinical role, it&#8217;s fairly easy to take the blame for most bad things that happen to my patients. I give them cytotoxic chemotherapy (for good reason, honest) and it&#8217;s a group of substances that we label with TERATOGENIC! HARMFUL! QUITE BAD FOR YOU! tags a lot of the time.<\/p>\n<p>But how do we know, in most circumstances, if the \u00a0drug\/potion\/puffer etc is the cause of something averse?\u00a0<!--more--><\/p>\n<p>The basic tenets of appraisal for such an study\u00a0are about assembling an appropriate group, and making fair assessments of outcomes &#8211; much as every other type of study.<\/p>\n<p>You&#8217;d like to see that<\/p>\n<ul>\n<li>the exposed &amp; unexposed groups were broadly comparable<\/li>\n<li>the outcomes and <a href=\"https:\/\/stg-blogs.bmj.com\/adc\/2009\/02\/13\/confused-by-confounding\/\">confounding <\/a>variables were measured the same way<\/li>\n<li>the follow-up was long enough to have seen the outcome happen<\/li>\n<\/ul>\n<p>These try to see if there&#8217;s something else in the patient\/group that is the &#8217;cause&#8217; of the poor outcomes, that it&#8217;s not just that one group got extra-hard looking-at, and that we waited long enough to see if it was bad or not.<\/p>\n<p>There are some additional, common-sense type questions that need to be asked too:<\/p>\n<ul>\n<li>did exposure-to-harm-causing-agent really happen before the harm was caused?<\/li>\n<li>is there a dose-response gradient? (mostly this is found)<\/li>\n<li>is there challenge-rechallenge data? (if it happens three times, it&#8217;s pretty much that it did happen)<\/li>\n<li>is the association consistent across studies? (that&#8217;s consistent &#8211; not identical &#8211; or is this a one-off finding in one study?)<\/li>\n<li>does the association make biological sense? (bearing in mind that biological sense is often rewritten when we see things that didn&#8217;t make sense until we explained them &#8230;)<\/li>\n<\/ul>\n<p>Now the idea way of getting comparable groups is randomisation, but if the events are rare or temporally late from giving the drug, it&#8217;s not going to catch them. It might be that large cohorts, or case-control studies are needed instead. For exceptionally rare events, then\u00a0collections of cases (without formal controls) may be sufficient to show the harms caused.<\/p>\n<p>&#8216;Blaming&#8217; is always difficult, but these appraisal pointers may be of some use in unpicking the strength of evidence behind the attributions.<\/p>\n<p>&#8211; Archi<!--TrendMD v2.4.8--><\/p>\n","protected":false},"excerpt":{"rendered":"<p>In my clinical role, it&#8217;s fairly easy to take the blame for most bad things that happen to my patients. I give them cytotoxic chemotherapy (for good reason, honest) and it&#8217;s a group of substances that we label with TERATOGENIC! HARMFUL! QUITE BAD FOR YOU! tags a lot of the time. But how do we [&#8230;]<\/p>\n<p><a class=\"btn btn-secondary understrap-read-more-link\" href=\"https:\/\/stg-blogs.bmj.com\/adc\/2016\/03\/11\/basics-blame-it-on-me\/\">Read More&#8230;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[79,80],"tags":[],"class_list":["post-1265","post","type-post","status-publish","format-standard","hentry","category-archimedes","category-critical-appraisal-note"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/posts\/1265","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/comments?post=1265"}],"version-history":[{"count":0,"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/posts\/1265\/revisions"}],"wp:attachment":[{"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/media?parent=1265"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/categories?post=1265"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/tags?post=1265"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}