Evidence-Based Medicine in Uveitis

The practice of medicine is based on applying what we have learned from our medical training, in addition to the knowledge gained by reading books and articles and attending scientific conferences. It is our hope, for example, that the book you are reading will assist you in the care of patients with uveitis. However, all medical literature, including our book, must be read critically. Much of the information that appears to be irrefutable scientific dogma is actually based on inconclusive data derived from a handful of patients. Because the recommendations are in print and stated by seemingly reputable authorities, they are often followed blindly. It is useful to thoroughly review the original references on which various therapeutic approaches are based; what you find may surprise you.

There is a growing movement to base treatment decisions on evidence-based medicine. The practice of evidence-based medicine is defined as the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. Evidence-based medicine has been divided into two types: evidence-based guidelines and evidence-based individual decision making. In each case, the goal is to base therapy on the best evidence available. A number of classifications for the quality of evidence have been proposed. Many of these classifications are derived from a rating system described in a report by the Canadian Task Force on the Periodic Health Examination in 1979. One commonly used stratification was proposed by the U.S. Preventive Services Task Force and is detailed in Table 7.1 . An assessment of the quality of the information in the literature is critical in determining the best treatment for our patients.

When treatment recommendations are made in published guidelines or in the literature, they can be graded based on the strength of the data and used to provide suggestions for clinical practice. The U.S. Preventive Services Task Force updated its grade definitions in 2012, and they are listed in Table 7.2 .

When you read the medical literature, it is important to determine the experimental methods used in the various studies. Sometimes this information can be discerned from the title of the paper; at other times, the Methods section must be read. Occasionally, the study method is not stated in the paper: if this is the case, the article is probably not worth reading. Many of the clinical studies in the literature are retrospective; that is, the data reported by the study were collected from past patient visits. Retrospective studies can provide valuable information but are usually limited by the quality and thoroughness of patient records. A patient’s symptoms and clinical findings, although present, are often not recorded. For example, if there is no comment in a patient’s record about vitreous haze, does this mean that vitreous haze was absent or that it was present but not recorded in the note? Fortunately, most ophthalmic notes contain a core of data, including visual acuity, intraocular pressure, and results of anterior segment and retinal examination. Nevertheless, prospective studies are less prone to errors when specific data are collected during patient visits on specifically designed case report forms.