Features August 2007 Issue

Clinical Trials: What the Terms Mean

Deciphering the research lingo can help you determine whether you should ask your doctor about a new drug or treatment.

Itís tough to go a week without seeing a newspaper or TV report about some new research study related to arthritis. But in many cases, research stories donít come with an explanation key. Instead, youíre left on your own to determine if a studyís

implications may be a long way off or are something you need to discuss with your doctor now.

The arthritis story that makes headlines could come from anywhere on the research spectrum, from basic laboratory science all the way to final-stage clinical testing. To make sense of any research study, first determine its place on this continuum.

Following are four types of research studies used to develop new drugs or treatments for arthritis. Some trial results may only be suggestive, while others can yield solid breakthroughs that can change the practice of medicine in diagnosis and treatment.

Randomized Clinical Trial.

This is considered the gold standard of research studies, since it leaves the least room for statistical bias. Rather than select who gets the experimental treatment and who gets the placebo, investigators randomly assign participants to one of the two options. To counter any influence a personís expectations may have on a treatmentís effectiveness, all participants are "blinded" figuratively, so they donít know which treatment they are getting. In a "double-blinded" study, neither participants nor researchers know who is getting what treatment. This eliminates any bias by investigators and ensures the study will have maximum statistical power.

Cohort Study.

Undertaken when a randomized trial is not feasible, in a cohort study half the participants are chosen to get the new treatment, and half get standard therapy. Participants are followed over time to compare results of treatment. A cohort study is less statistically rigorous than a randomized trail since bias can creep in as both investigators and participants know up front who is getting what treatment.

Retrospective Study.

By interviewing participants or examining their medical records, this study looks back in time at participant histories to identify risk factors that may have led to the onset of the disease. This study is limited by the reliability of participant recollections and the accuracy of their medical records.

Meta-Analysis Study.

A meta-analysis study combines the results from several smaller studies that have examined the same issue to reach larger, more statistically significant conclusions. Not a clinical trial, a meta-analysis studyís value is only as good as the quality of the studies on which it is based.