REPORTING, CREDIBILITY, AND ESTIMATION OF ANCHOR-BASED MINIMAL IMPORTANT DIFFERENCE FOR PATIENT-REPORTED OUTCOME MEASURES

Abstract

Patient-reported outcome measures (PROMs) are becoming an integral part of healthcare decision making. Clinical trials, systematic reviews, and clinical practice guidelines incorporate them to learn about the effect of medical interventions in patients’ health status, without interference or mediation from clinicians or proxies. The use of these types of measures, however, is not without challenges. In particular, the complexity of the PROMs makes it difficult for patients, clinicians, and researchers to fully grasp the extent to which a treatment effect is negligible or trivial, small but important, moderate, or large. One of the most documented ways to address this issue is the use of the minimal important difference (MID), the smallest change in a PROM, either beneficial or harmful, that patients would perceive as important. A patient-oriented way to determine this threshold is the estimation of an anchor-based MID, where PROM results are compared against an external independent criterion the anchor that is in itself understandable and relevant for patients. This dissertation is an effort to facilitate the identification, evaluation, and utilization of MID estimates for PROMs. First, this thesis describes the development and reliability assessment of a new instrument to determine the credibility of primary studies ascertaining MID estimates, Second, it describes the conduct of a systematic survey to inform the creation of an inventory of all available anchor-based MIDs in the medical literature until 2015. Third, it reports an analysis of the state of the art of current MID estimates from a reporting and credibility perspective. Finally, this work concludes with a summary of the main results, presentation of strengths and limitations, and insights related to the implications for future research.