Are therapeutic decisions supported by evidence from health care research?

Background: One of the most common decisions physicians face is deciding which therapeutic intervention is the most appropriate for their patients. In recent years much emphasis has been placed on making clinical decisions that are based on evidence from the medical literature. Despite the emphasis on incorporation of evidence-based medicine into the undergraduate curriculum and postgraduate medical training programs, there has been controversy regarding the proportion of interventions that are supported by health care research. Objective: To investigate the proportion of major therapeutic interventions at our institution that are justified by published evidence. Methods: One hundred fifty charts from the internal medicine department were reviewed retrospectively. The main diagnosis, therapy provided, and patient profile were identified and a literature search using MEDLINE was performed. A standardized search strategy was developed with high sensitivity and specificity for identifying publication quality. The level of evidence to support each clinical decision was ranked according to a predetermined classification. In this system there were 6 distinct levels, which are explained in the study. Results: Of the decisions studied, 20.9% could be supported by placebo-controlled randomized trials and 43.9% by head-to-head trials. Half of these were shown to be significantly superior to the treatment against which it was being compared. For 10 of the 150 clinical decisions, evidence was found demonstrating alternative therapies as being more effective than that selected. Conclusions: Most primary therapeutic clinical decisions in 3 general medicine services are supported by evidence from randomized controlled trials. This should be reassuring to those who are concerned about the extent to which clinical medicine is based on empirical evidence. This finding has potential for quality assurance, as exemplified by the discovery that a literature search could have potentially improved these decisions in some cases.