What type of clinical evidence is needed to assess medical devices?

The objective of the paper is to discuss the role of Real World (RW) studies as a source of clinical evidence when experimental studies, such as Randomized Control Trials (RCTs) are not available. Waiting for RCT evidence when the technology is diffusing could be anti-economical, inefficient from the policy perspective and methodologically questionable. We explain how RW studies could provide relevant evidence to decision makers. Matching techniques are discussed as a viable solution for bias reduction. We describe a case study concerning a cost-effectiveness analysis (CEA) based on real-world data of a technology already in use: Mitraclip combined with medical therapy versus medical therapy alone, in patients with moderate to severe mitral regurgitation. The CEA has encountered the scepticism of most reviewers, due not to the statistical methodology but to the fact that the study was observational and not experimental. Editors and reviewers converged in considering real-world economic evaluations premature in the absence of a RCT, even if in the meanwhile the technology had been implanted more than 30,000 times. We believe there is a need to acknowledge the importance of RW studies and engage the scientific community in the promotion and use of clinical evidence produced through observational studies.