Case studies to explore the optimal use of randomized and nonrandomized studies in evidence syntheses that use GRADE

OBJECTIVES: Randomized controlled trials (RCTs) are the preferred source of evidence for the relative effect of healthcare interventions summarized in knowledge syntheses. Nonrandomized studies of interventions (NRSI) may provide replacement, sequential, or complementary evidence to RCTs. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach can provide different options for properly using RCTs and NRSI …