Evidence-Based Surgery

Abstract

Evidence-based surgery describes the consistent and judicious use of the best available scientific evidence in making decisions about the care of surgical patients. In this chapter, guidelines and secondary sources of scientific evidence are provided. Examples include Clinical Evidence, the Cochrane Database of Systematic Reviews, and the Institute for Healthcare Improvement. Levels of evidence are defined. Appraising scientific evidence via specific study designs is described, including studies’ internal and external validity (generalizability). In evaluating the quality of a study, the properties of chance (Type I and Type II errors); bias (selection bias and measurement bias); and confounding (along with randomization, restriction and matching, instrumental variable analysis, stratification, and propensity score risk adjustment) are defined. Interpreting and applying evidence to practice (external validity) are discussed. A discussion of evidence-based surgery and quality of care is provided and focuses on how efforts to assess quality on evidence-based processes of care or clinical outcomes are as much practical as philosophical. A figure shows processes that affect the internal and external validity of a clinical study. Tables show levels of evidence, as stratified by the U.S. Preventive Services Task Force, and methods observed in published clinical studies that demonstrate efforts to minimize the effects of chance, bias, and confounding. This review contains 1 figure, 3 tables, and 42 references.