What is High-Quality Medical Research (Part I)?
June 2nd 2009 17:54
Overwhelmed by the amount of conflicting health headlines? With the huge barrage of medical/health information bombarded at us everyday, how do we know what to believe?
High quality evidence for a relationship between a given substance (for example cranberries) and disease (for example urinary tract infection) is judged by considering peer-reviewed (more on this forthcoming) scientific studies and publicly available data that report on these associations. This is called Evidence Based Medicine. A simple explanation is that when enough high-quality researched has been published on a given subject, then conclusions can be firmly drawn (cranberries prevent urinary tract infections).
Specific types of studies are often referred to when analyzing the scientific literature. These are: systematic reviews of the medical literature (focusing on a single question and synthesizing all the high quality evidence pertaining to that topic), large randomized controlled trials (random allocation of a given treatment to a group of participants), and large prospective studies (followed up over time). Reports of the experiences of individual patients or small groups usually provide less reliable evidence.
Typically media coverage centers around one recently published study, without putting that study in context. If one study claims that X causes Y, but four other studies claim that X has no relationship to Y, then the general scientific consensus is that there is no relationship between X and Y. Unfortunately the 24 hour news cycle often does not allow for careful background research before the media hypes the latest 'breakthrough'. This doesn't mean that everything you hear on the news is wrong, it is just not placed within the context of the body of evidence on a given topic. This leads to great public confusion when one day you hear that X may be good for you, and then next week hear that it's bad for you.
Believe it or not, there are a variety of standards that exist for judging the quality of evidence. Many US organizations (and throughout the world) have published standards by which to judge. The FDA (Food and Drug Administration), AHRQ (Agency for Healthcare Research and Quality), and the WHO (World Health Organization), to name a few, all have standards for the quality of evidence on which they base decisions. The Harvard School of Public Health has a nice in-depth explanation of some of the things mentioned here.
Coming Soon... Part II - What separates the good from the bad?
High quality evidence for a relationship between a given substance (for example cranberries) and disease (for example urinary tract infection) is judged by considering peer-reviewed (more on this forthcoming) scientific studies and publicly available data that report on these associations. This is called Evidence Based Medicine. A simple explanation is that when enough high-quality researched has been published on a given subject, then conclusions can be firmly drawn (cranberries prevent urinary tract infections).
Specific types of studies are often referred to when analyzing the scientific literature. These are: systematic reviews of the medical literature (focusing on a single question and synthesizing all the high quality evidence pertaining to that topic), large randomized controlled trials (random allocation of a given treatment to a group of participants), and large prospective studies (followed up over time). Reports of the experiences of individual patients or small groups usually provide less reliable evidence.
Typically media coverage centers around one recently published study, without putting that study in context. If one study claims that X causes Y, but four other studies claim that X has no relationship to Y, then the general scientific consensus is that there is no relationship between X and Y. Unfortunately the 24 hour news cycle often does not allow for careful background research before the media hypes the latest 'breakthrough'. This doesn't mean that everything you hear on the news is wrong, it is just not placed within the context of the body of evidence on a given topic. This leads to great public confusion when one day you hear that X may be good for you, and then next week hear that it's bad for you.
Believe it or not, there are a variety of standards that exist for judging the quality of evidence. Many US organizations (and throughout the world) have published standards by which to judge. The FDA (Food and Drug Administration), AHRQ (Agency for Healthcare Research and Quality), and the WHO (World Health Organization), to name a few, all have standards for the quality of evidence on which they base decisions. The Harvard School of Public Health has a nice in-depth explanation of some of the things mentioned here.
Coming Soon... Part II - What separates the good from the bad?
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