ABSTRACT
Quality of evidence is an important consideration when making a therapeutic decision, in that it is the best predictor of consistent clinical outcome. Quality of evidence can be graded from 1 to 4; grades 1 and 2 comprise the highest level of evidence, consisting of systematic reviews (meta-analyses) and well designed, properly randomized, controlled, patient-centered clinical trials (RCCTs). Grade 3 denotes a moderate level of evidence, consisting of well designed, non-RCCTs, epidemiological studies (cohort, case–control), models of disease, and dramatic results in uncontrolled studies. Grade 4 is the lowest level of evidence, encompassing expert opinions, descriptive studies, studies in non-target species, pathophysiologic findings, and in vitro studies ( 3.1 ). Very few reports have been made reviewing the quality of evidence of treatments for osteoarthritis (OA) in dogs 1,2 .
