Making Sense of Medical Research Studies

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What do I need to know about health research?

There are many different areas of health research and many different ways of collecting information.

  • Biomedical or basic research : studies done on cells, tissue or animals, often in a laboratory. They may or may not be relevant to humans. They often only suggest directions for research.
  • Epidemiological research : studies of groups of people (populations) to look at patterns in the rates, distribution, prevention and control of disease, injuries, and other health-related events.
  • Social and behavioural research : studies that look at people’s attitudes, needs and practices.
  • Clinical research : studies the diagnosis, treatment, prevention, and outcomes of diseases or conditions. They include intervention studies, such as clinical trials and community-based trials that look at whether a strategy, drug, or medical treatment is safe and works to treat or prevent a health-related event.
  • Health services and operational research : studies how health care is delivered and how people access health care.

What kinds of information do researchers look at?

There are two general kinds of studies: “quantitative” and “qualitative”. The kind of study that a researcher does depends on the question that’s being asked.

  • Quantitative studies are the kind most often used in medical research, especially when looking at drugs and other treatments. These studies as questions such as “how many?” or “how much?” They count, measure, and compare things. For example, a quantitative study may count how many women taking a drug for heart disease developed heart disease. Or, they may measure how much of a drug is needed to prevent heart disease. Another study might compare two drugs that prevent heart disease to see which one works better and has fewer side effects.
  • Qualitative studies ask questions such as “why?” and “how?” This kind of research often uses interviews, surveys or other ways to observe people to find out how people think, feel, or act. For example, a qualitative study may ask: “Why do girls start smoking?” Qualitative studies ask questions that are hard, or not even possible, to answer with numbers.

What type of medical research is should I look at when I’m making decisions about my health?

Different types of medical research have different levels of credibility and ability to examine health practices. It is difficult to do a completely accurate, comprehensive study. Each study may have some weaknesses and some strengths. The types of studies and their levels of evidence, from the strongest to the weakest, are:

  • Systematic Reviews and Meta-Analysis : Comprehensive and structured review of all studies on a specific topic, sometimes combines the data or statistics from the studies (meta-analysis).
  • Randomized Controlled Studies : Randomly assigns study participants into two groups: those who get the treatment (case) and those who do not (control) to look for differences between the two groups. The chance of being in either group is 50/50. It does not depend on things like how much a person needs treatment. A stronger form of this type of study is the Randomized Controlled Double-Blind Study. This form has the extra step of making sure that neither the researchers nor the study participants know who is getting the treatment or the placebo (sugar pill) until the end of the study.
  • Cohort Studies : Observes a clearly defined group of people either forward in time (prospective) or looking back in time (retrospective) at previous medical records and other information.
  • Case-Control Studies : Compares two groups of people: people with a disease or condition (cases) to other people who have the same characteristics (such as age and sex) who do not have that condition (controls).
  • Case Series : Describes of a number of ‘cases’.
  • Case Reports : Reports on a single case.
  • Ideas, Editorials, and Opinions .
  • Animal Research .
  • In Vitro (Test Tube) Research .

How are studies funded?

Funding for research usually comes from government departments, foundations, universities or corporations. It is important to ask where the money comes from because some funders may have a financial interest in what the study says. For example, a drug company paying for research on their drug may want the researchers to show that the drug is effective. Researchers are more frequently telling (disclosing) where the funding for the study came from right on the research paper or journal article.

Did the researchers study people like me?

Did the researchers study men only, or women and men, or women only? Were the study participants from a wide range of backgrounds and ages? If the researchers studied only certain types of women, their findings may not apply to all women.

Until recently medical research has tended to study men and not recognize that there are differences between men’s and women’s health. Now, researchers are trying more to understand those differences using “gender-based analysis” or “GBA”.

Was the group studied large enough? When a quantitative study looks at whether one treatment is better than another, or has dangers or side effects, researching a large population over a long period of time gives results that are more meaningful.

Small groups are often used in qualitative studies. These studies look at an issue in-depth and can take a lot of time, so it is not always possible to have a large study group.

How do I make sense of the statistics?

Statistics are supposed to show whether something just happens by chance or because of the treatment that is being studied. Saying that statistics are ‘significant’ means that the research results show that there is a meaningful difference between the groups in the study and that the differences are so big that they are probably not due to chance. The difference between to two groups is then due either to the treatment that is being studied, or an error or bias in the study.

Statistics can also be used to show whether two things occur together, how large a difference is, the combined effects of many factors, or how something changes over time.

Research studies look at groups of people and its results may or may not apply to you. Talk with a health professional about whether the result of a medical study applies to you and your particular medical history, needs, and experiences.

What are some examples of potential bias in medical studies?

Biases are things that influence the results of a research study. Different sources of bias can affect the study design, the data analysis, or the interpretation of the study results.

  • Medical research may focus on one disease or condition and only look at how some aspects of women’s lives affect the condition.
  • Some people feel better when they think they are receiving treatment, even if they are only getting a sugar pill. This is called the placebo effect.
  • People’s memories are selective and volunteers can under or overestimate answers to research questions. People sometimes give answers that they think are the ‘right’ ones or what the researchers want to hear.
  • Sometimes, observations and conclusions may be influenced by stereotypes about groups of people.
  • There might be problems in the way that people were chosen or volunteer for the study so that the study participants are not representative of the larger society.

How do I judge the results?

  • Did the study do what it set out to do?
  • Do the conclusions follow from the information presented?
  • Does the study overestimate benefits or underestimate dangers?
  • If the study suggests drugs or therapies for prevention was there long-term follow-up on the effects?
  • Do the results fit with older, more established evidence? Sometimes new research findings challenge established evidence.